Washington (CNN) Sometimes he calls to ask for advice. Other times he just wants to vent.

But nearly every day of his presidency, President Donald Trump has picked up the phone and turned to a network of more than two dozen fellow billionaires and millionaires, sports figures and informal advisers outside the White House.

Trump has struggled in many ways to apply his decades of experience in real estate and entertainment to governing in his first 100 days in office. But he's had no problem maintaining the same kind of line of communication that he relied on during his decades in business and throughout his unconventional campaign. It's now a fundamental part of how he's running the country, according to a half-dozen friends and advisers familiar with the calls.

The network of outsiders with whom Trump speaks regularly have also served as a key bulwark to the isolation every president feels at one point or another at the White House -- an effect magnified for Trump, who took office with few true friends in Washington after his establishment-bashing campaign ended in unexpected victory.

Hello?

Nearly every day of his young presidency, Trump has picked up the phone to seek counsel, friendship and fresh perspective from dozens of people: He's reached out to decades-old sounding boards like Tom Barrack and Phil Ruffin, "winning" sports figures like retired Indiana basketball coach Bobby Knight and Patriots coach Bill Bellichick, as well as political advisers like his former campaign manager, Corey Lewandowski and Rudy Giuliani, New York's former mayor.

The calls come at all hours of the day: in the evenings, late at night and sometimes as early as "three or four o'clock in the morning" -- whenever inspiration strikes -- said one source who speaks regularly with Trump. They typically lack a set agenda and are marked by Trump's propensity for bouncing from one subject to the next, according to friends and advisers familiar with the calls, one of whom described calls with Trump as "stream of consciousness."

But that doesn't mean Trump is looking to come up empty-handed after hanging up the phone.

"He gets a lot of opinions," said Ruffin, the casino magnate who has been friends with Trump for two decades. "He just gets other views ... as many views as he can ... and then makes the final decision on what he wants to do."

Ruffin described his calls with Trump, who was best man at Ruffin's 2008 wedding, as "friendly conversations" that sometimes veered toward policy issues, though he declined to offer details, calling the conversations confidential.

Others who have spoken to Trump since he took office said the President has sought their advice on policy issues, but also calls to ask for their reviews of his latest actions, amassing a bank of feedback -- and sometimes even criticism -- of his progress as president and the performance of his White House advisers.

"His circle of friends is large and deep. And he has relied on these people to give him honest input regardless of what the issue is," said a source close to Trump who speaks with him regularly. "Most of the people that he speaks to are contemporaries of his who don't need or want anything from him."

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Breaking out of the bubble

It's a model Trump pulled from his decades in real estate and casinos and is now putting to the test at the White House, where it's also serving as a way for Trump to break out of the "bubble" the presidency can foster.

"The White House is very -- there's only so much information you're going to get. You're limited," the source said. "The President likes to get as much information as possible from as many people as possible."

The calls are also an outlet for his frustrations, coming as bad news days ended and Trump retreated to the privacy of his White House residence, where he is often alone as first lady Melania Trump continues to live in New York.

It's often when he's alone that he's picked up the phone and fumed about the Republican Congress' failure to pass health care reform, or unfavorable coverage in the media.

When his attorney general recused himself from investigations into Russian involvement in the 2016 campaign amid political pressure from Democrats, a livid Trump dialed one of his friends outside government and unleashed an expletive-laced rant, according to a source familiar with the call.

Most presidents reach outside their circle of advisers inside the White House to get outside perspectives, but presidential historian Douglas Brinkley said past presidents have typically used relied on former government officials and "so-called wise men" for advice.

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'Wise men'

Trump does take the counsel of some of those "wise men," albeit those with an anti-establishment streak like Newt Gingrich, the former House speaker. ( The New York Times reported Saturday Trump counts at least 20 confidantes.)

Unlike the small group of friends Trump frequently phones, Gingrich said his relationship with Trump isn't a "social chit-chat relationship," but more politically oriented -- though, "if he has time, he chats at length," said Gingrich.

"I think that he tries to sort through what he learns from a wide range of sources," said Gingrich, who speaks with Trump occasionally. "What you end up with is somebody who gathers information from an amazing range of sources, forms intuitive opinions about what it all means and then finds himself making decisions."

Current House Speaker Paul Ryan has also begun fielding calls from the President. A source familiar with the calls said they've come both late at night and early in the morning, during Ryan's gym workout.

But Trump is largely sticking to the counsel of longtime friends and outsider advisers.

And that can sometimes be an enabling force that fuels some of his worst impulses -- whether by reaffirming his attacks on the media or sharing personal anecdotes that Trump later seizes on as evidence to support his political views and sometimes his most unfounded opinions.

During the campaign, Trump often let his conversations with friends and business associates spill into his stump speech. One friend couldn't afford to buy Caterpillar tractors anymore and had been forced to turn to the US manufacturer's Japanese competitor, Komatsu. Another friend told Trump he had stopped going to France after a spate of recent terrorist attacks, declaring, "France is no longer France."

And days into his presidency, Trump cited a story about potentially unlawful activity at a polling place on Election Day as evidence of his debunked claim that millions of illegal votes were cast in the 2016 election.

Now, those calls are informing policy.

As he signed executive actions in February aimed at rolling back financial reform regulations enacted under the Dodd-Frank Act, Trump cited the plight of fellow millionaire and billionaire businessmen.

"We expect to be cutting a lot from Dodd-Frank because, frankly, I have so many people -- friends of mine -- that have nice businesses, they can't borrow money. They just can't get any money because the banks just won't let them borrow it because of the rules and regulations in Dodd-Frank," Trump said, contradicting public data that shows bank lending has been consistently on the rise since the law went into effect in 2010.

Photos: Donald Trump's rise President-elect Donald Trump has been in the spotlight for years. From developing real estate and producing and starring in TV shows, he became a celebrity long before winning the White House. Hide Caption 1 of 37 Photos: Donald Trump's rise Trump at age 4. He was born in 1946 to Fred and Mary Trump in New York City. His father was a real estate developer. Hide Caption 2 of 37 Photos: Donald Trump's rise Trump, left, in a family photo. He was the second-youngest of five children. Hide Caption 3 of 37 Photos: Donald Trump's rise Trump, center, stands at attention during his senior year at the New York Military Academy in 1964. Hide Caption 4 of 37 Photos: Donald Trump's rise Trump, center, wears a baseball uniform at the New York Military Academy in 1964. After he graduated from the boarding school, he went to college. He started at Fordham University before transferring and later graduating from the Wharton School, the University of Pennsylvania's business school. Hide Caption 5 of 37 Photos: Donald Trump's rise Trump stands with Alfred Eisenpreis, New York's economic development administrator, in 1976 while they look at a sketch of a new 1,400-room renovation project of the Commodore Hotel. After graduating college in 1968, Trump worked with his father on developments in Queens and Brooklyn before purchasing or building multiple properties in New York and Atlantic City, New Jersey. Those properties included Trump Tower in New York and Trump Plaza and multiple casinos in Atlantic City. Hide Caption 6 of 37 Photos: Donald Trump's rise Trump attends an event to mark the start of construction of the New York Convention Center in 1979. Hide Caption 7 of 37 Photos: Donald Trump's rise Trump wears a hard hat at the Trump Tower construction site in New York in 1980. Hide Caption 8 of 37 Photos: Donald Trump's rise Trump was married to Ivana Zelnicek Trump from 1977 to 1990, when they divorced. They had three children together: Donald Jr., Ivanka and Eric. Hide Caption 9 of 37 Photos: Donald Trump's rise The Trump family, circa 1986. Hide Caption 10 of 37 Photos: Donald Trump's rise Trump uses his personal helicopter to get around New York in 1987. Hide Caption 11 of 37 Photos: Donald Trump's rise Trump stands in the atrium of the Trump Tower. Hide Caption 12 of 37 Photos: Donald Trump's rise Trump attends the opening of his new Atlantic City casino, the Taj Mahal, in 1989. Hide Caption 13 of 37 Photos: Donald Trump's rise Trump signs his second book, "Trump: Surviving at the Top," in 1990. Trump has published at least 16 other books, including "The Art of the Deal" and "The America We Deserve." Hide Caption 14 of 37 Photos: Donald Trump's rise Trump and singer Michael Jackson pose for a photo before traveling to visit Ryan White, a young child with AIDS, in 1990. Hide Caption 15 of 37 Photos: Donald Trump's rise Trump dips his second wife, Marla Maples, after the couple married in a private ceremony in New York in December 1993. The couple divorced in 1999 and had one daughter together, Tiffany. Hide Caption 16 of 37 Photos: Donald Trump's rise Trump putts a golf ball in his New York office in 1998. Hide Caption 17 of 37 Photos: Donald Trump's rise An advertisement for the television show "The Apprentice" hangs at Trump Tower in 2004. The show launched in January of that year. In January 2008, the show returned as "Celebrity Apprentice." Hide Caption 18 of 37 Photos: Donald Trump's rise A 12-inch talking Trump doll is on display at a toy store in New York in September 2004. Hide Caption 19 of 37 Photos: Donald Trump's rise Trump attends a news conference in 2005 that announced the establishment of Trump University. From 2005 until it closed in 2010, Trump University had about 10,000 people sign up for a program that promised success in real estate. Three separate lawsuits -- two class-action suits filed in California and one filed by New York's attorney general -- argued that the program was mired in fraud and deception. Trump's camp rejected the suits' claims as "baseless." And Trump has charged that the New York case against him is politically motivated. Hide Caption 20 of 37 Photos: Donald Trump's rise Trump attends the U.S. Open tennis tournament with his third wife, Melania Knauss-Trump, and their son, Barron, in 2006. Trump and Knauss married in 2005. Hide Caption 21 of 37 Photos: Donald Trump's rise Trump wrestles with "Stone Cold" Steve Austin at WrestleMania in 2007. Trump has close ties with the WWE and its CEO, Vince McMahon. Hide Caption 22 of 37 Photos: Donald Trump's rise For "The Apprentice," Trump was honored with a star on the Hollywood Walk of Fame in January 2007. Hide Caption 23 of 37 Photos: Donald Trump's rise Trump appears on the set of "The Celebrity Apprentice" with two of his children -- Donald Jr. and Ivanka -- in 2009. Hide Caption 24 of 37 Photos: Donald Trump's rise Trump poses with Miss Universe contestants in 2011. Trump had been executive producer of the Miss Universe, Miss USA and Miss Teen USA pageants since 1996. Hide Caption 25 of 37 Photos: Donald Trump's rise In 2012, Trump announces his endorsement of Republican presidential candidate Mitt Romney. Hide Caption 26 of 37 Photos: Donald Trump's rise Trump speaks in Sarasota, Florida, after accepting the Statesman of the Year Award at the Sarasota GOP dinner in August 2012. It was shortly before the Republican National Convention in nearby Tampa. Hide Caption 27 of 37 Photos: Donald Trump's rise Trump appears on stage with singer Nick Jonas and television personality Giuliana Rancic during the 2013 Miss USA pageant. Hide Caption 28 of 37 Photos: Donald Trump's rise In June 2015, during a speech from Trump Tower, Trump announced that he was running for President. He said he would give up "The Apprentice" to run. Hide Caption 29 of 37 Photos: Donald Trump's rise Trump -- flanked by U.S. Sens. Marco Rubio, left, and Ted Cruz -- speaks during a CNN debate in Miami on March 10. Trump dominated the GOP primaries and emerged as the presumptive nominee in May. Hide Caption 30 of 37 Photos: Donald Trump's rise The Trump family poses for a photo in New York in April. Hide Caption 31 of 37 Photos: Donald Trump's rise Trump speaks during a campaign event in Evansville, Indiana, on April 28. After Trump won the Indiana primary, his last two competitors dropped out of the GOP race. Hide Caption 32 of 37 Photos: Donald Trump's rise Trump delivers a speech at the Republican National Convention in July, accepting the party's nomination for President. "I have had a truly great life in business," he said. "But now, my sole and exclusive mission is to go to work for our country -- to go to work for you. It's time to deliver a victory for the American people." Hide Caption 33 of 37 Photos: Donald Trump's rise Trump faces Democratic nominee Hillary Clinton in the first presidential debate, which took place in Hempstead, New York, in September. Hide Caption 34 of 37 Photos: Donald Trump's rise Trump apologizes in a video, posted to his Twitter account in October, for vulgar and sexually aggressive remarks he made a decade ago regarding women. "I said it, I was wrong and I apologize," Trump said, referring to lewd comments he made during a previously unaired taping of "Access Hollywood." Multiple Republican leaders rescinded their endorsements of Trump after the footage was released. Hide Caption 35 of 37 Photos: Donald Trump's rise Trump walks on stage with his family after he was declared the election winner on November 9. "Ours was not a campaign, but rather, an incredible and great movement," he told his supporters in New York. Hide Caption 36 of 37 Photos: Donald Trump's rise Trump is joined by his family as he is sworn in as President on January 20. Hide Caption 37 of 37

'Everything ... is strategic'

The White House held up Trump's contact with friends and informal advisers as a way for the President to get a range and diversity of opinions and, ultimately, an asset.

"Everything he does is strategic, especially his many relationships and constant communication with a vast network of individuals," Trump spokeswoman Hope Hicks said in an email.

Trump has displayed his desire to aggregate information in public as well, albeit from selective sources, turning campaign rallies into public polling opportunities and asking invited guests as events he attends for inputs on hiring decisions -- like he did during the vice presidential and Cabinet nominee search process.

Chris Ruddy, founder and CEO of the conservative news site Newsmax who befriended Trump more than a decade ago, called Trump a "moving, roving focus group post" and said he believes Trump "will be the most accessible president in modern times."

"It makes people feel like they're part of his decision-making process and, second, it does give him information he might not get from others," said Ruddy, who met with Trump in the Oval Office last week and has spoken with him several times in recent weeks at Trump's Mar-a-Lago club, where Ruddy is a member.

Trump's habit of hopping on the phone can also be a way of garnering good will. Trump will sometimes call people he's never met but sees speaking favorably on TV to "congratulate them on doing a great job," a source close to Trump said.

The calls are also simply about keeping in touch, one close Trump adviser said.

"He's a human being and these aren't people he's necessarily calling for advice or input. They're his friends," the longtime adviser said.

Chris Christie, the governor of New Jersey and one of Trump's top campaign surrogates who has been friends with Trump for nearly two decades, told The New York Times this month that while Trump often calls for advice, the two sometimes "don't talk about business at all."

"He'll be shooting the bull about sports or some show he saw on television or a movie or whatever, or he'll be asking me about (my wife) Mary Pat and the kids," Christie said.

One former campaign official also described the calls in social terms: "You get a beer with buddies, he gets on the phone with a bunch of people."