Half a billion. Minimum. That’s how much funding Donald Trump is likely to need if he becomes the GOP presidential nominee and runs against Hillary Clinton in the fall.

The estimate comes from Anthony Scaramucci, founder of the hedge fund Skybridge Capital, who’s a prominent Republican donor. “If you do the math, he’ll need 15,000 $33,000 checks,” Scaramucci tells me in the video above. “That’s $495 million. He’s late to the party on that. If he’s going to be the nominee, he needs to start organizing that now.”

Scaramucci is referring to the maximum amount individual donors can give each year to the Republican and Democratic National Committees, which is $33,400. The party committees play a large role in funding the presidential campaigns, and the donation limit is the highest for any committee that’s allowed to be directly involved with a campaign. Super PACs have no limit on donations, but they’re not supposed to coordinate (wink, wink) with the candidates’ campaign committees.

So far, Trump has loaned his committee about $25 million of his own money, and drawn another $10 million in donations from supporters. And he’s pledged to spend as much as $100 million of Trumpbucks on the race. But even if he did, he’d fall way short of the scratch typically spent on a presidential race. In 2012, for instance each side spent roughly $1 billion.

That means Trump, if he’s the nominee, will need help raising money from the Republican establishment he’s been feuding with. Trump, for instance, has called the RNC’s rules for selecting a candidate “rigged.” He has also mocked many of the party’s big donors, who have so far blown more than $200 million on super PACs supporting failed candidates long gone from the race.

Some big donors seem to feel burned by the millions they’ve donated to losing candidates, and reluctant to keep spending so lavishly. Casino magnate Sheldon Adelson, for instance, spent about $100 million supporting super PACs affiliated with Newt Gingrich and Mitt Romney in 2012. So far, he has sat out the 2016 election, giving to nobody. But Scaramucci (who previously backed Scott Walker and Jeb Bush in the 2016 race and admits he’s 0 for 2) thinks wealthy donors will back Trump, as he long as he asks for their help. “There will be plenty of money for these candidates, including candidate Trump,” he says.

Assuming Hillary Clinton is the Democratic nominee, she’ll need to raise just as much money as her Republican opponent, if not more. But Clinton would start out with the full support of the Democratic National Committee and a large, well-oiled network of donors. She’s also got a huge head-start on super PAC funding, since the main Democratic group supporting her has about $45 million in the bank—and a lot more where that came from.

Trump may need to renege on his earlier pledge to forego super PAC support, and enlist megadonors to help fund turnout efforts, attack ads aimed at Clinton, and other types of politicking super PACs typically do. But Trump's deft exploitation of media coverage -- which earns him far more airtime than other candidates -- effectively counts as free publicity. And Scaramucci says Trump's fame as the star of the reality show "The Apprentice" since 2004 could compensate for the absence of a super PAC, if Trump goes without. “He built his presence ... with 15 million national viewers and a brand that stretches across the globe,” Scaramucci says. “It’s a brilliant strategy.” It might also save Republican donors some money this fall.

Rick Newman’s latest book is Liberty for All: A Manifesto for Reclaiming Financial and Political Freedom. Follow him on Twitter: @rickjnewman.