Such truly conspicuous consumption not long ago moved smart-alecky Phil Donahue to attempt to roast DJ good on live television. ''My God, Donahue,''

Trump fumes. ''He`s sitting over there in an apartment on 5th Avenue and he has the nerve to criticize me for living well? I will have created 16,000 jobs in Atlantic City, I pay tremendous taxes, we buy bonds for housing, and then I have to sit there and listen to Donahue tell me about greedy?''

Indeed, Trump came off much the better on that broadcast. ''The audience loved me.'' Hundreds of viewers wrote him. I was so embarrassed by Phil Donahue`s treatment of you . . . It`s unfortunate that jealousy makes people behave so badly . . . I will never watch him again. . . .

''He`s the people`s billionaire,'' says Ivana Trump, not without pride.

''You have no idea. Middle-class Americans adore Donald, and I don`t know why.

''They shouldn`t,'' she says. ''They should resent him. He`s young and wealthy and he flaunts it.''

''Yeah, I find I get along better with the construction workers and the cab drivers,'' Trump agrees. ''The people who count in the world. Working people respect the fact that I built this company by myself. People like Donahue, they don`t dig it. They`d like it for themselves.''

Surrounded by magazine covers of himself, arranged on his office wall in gilded frames, Trump is grumbling how fed up he is with sitting for interviews.

''I get 35 requests a day and I have no time to work.'' Dumb reporters give him a real pain. He is still smarting over the recent cover story in Time magazine. ''Shallow piece of . . .'' he seethes. ''I didn`t like that lady. A horrid reporter who sits there telling me she`s in the process of ripping off her husband in a divorce battle. She has this chip on her shoulder, and I`m saying to myself, why do I have to get this . . . .''

The Time profile had Trump conducting a spooky tour of the Manhattan triplex. ''They made me sound like Howard Hughes. I don`t consider myself eccentric, and I`m sick and tired of reading about how I buy, buy, buy. Nobody concentrates on the hard work to get the possessions. I built this company by myself.''

A `ROUGH, WILD` CHILD

Hard work, yes. Entirely by himself, not quite.

Born June 14, 1946, into a 23-room household in exclusive Jamaica Estates in Queens, Donald Trump was the fourth of five intensely competitive children cushioned in life by the $20 million amassed by Fred Trump, who had built 24,000 rent-controlled apartments in Brooklyn, Queens and Staten Island. At age 8, already riding bulldozers around construction sites, the boy was fantasizing about putting up big buildings himself. One day he borrowed his younger brother Robert`s toy blocks, glued them together into a towering skyscraper and never returned them.

Described by his father, now 83, as ''rough and wild,'' young Donald was packed off to the New York Military Academy at age 14; his disciplinarian father ''was a very firm, no-nonsense kind of guy who ruled by demeanor,''

Trump remembers. ''He never hit me.''

Amateur analysts have conventionally suggested that Trump is driven by a desperate need for paternal acceptance. ''Nonsense for sure,'' says Ivana Trump. Concedes DJ: ''I did want to prove to my father that I had the ability to be successful.''

That he did. At age 28, the baby-faced but cunning Wharton School graduate bragged he would change Manhattan`s skyline, at the very moment that the financially strapped city was unable to do anything for itself. With bluff and bravado and supreme chutzpah-and absolutely no track record-the young Trump secured options on the Hudson River railroad yards (now the site of New York`s Convention Center) and on the crumbling Commodore Hotel (now the Grand Hyatt). Then he persuaded bankers to lend him $80 million and pols to give him a $120 million tax abatement. At $10 million, he virtually took the Commodore like a thief in the night. (The Grand Hyatt, opened in 1980, today earns him $30 million annually.)

''You either have it or you don`t,'' Trump once reflected on Oprah Winfrey`s television show. ''Most people don`t.''

The Trump siblings, anything but flamboyant, accept their brother as the family ringleader. Sister Maryanne is a federal judge in Newark, sister Elizabeth an administrative assistant for Chase Manhattan. Older brother Fred, a onetime airline pilot, died of alcoholism in 1981 at age 43. ''My brother,'' Trump recalls with emotion, ''didn`t have a hunger for business, and he didn`t do well at it. I was devastated when he died.''

Younger brother Robert, whose building blocks Donald had swiped, has worked for the Trump organization since 1979, as executive vice president; and Trump is sensitive to their relationship. ''It must be tough for him,'' Trump says softly. ''But he`s a very self-assured man, and he has done a very effective job for me.''

ROASTING MAYOR KOCH

The rest is history, much of it still ongoing. Trump Tower, New York City`s tallest and most expensive reinforced concrete structure, opened for occupancy in 1982, after Trump won a widely criticized $50 million tax abatement. There was a long legal battle over 100 Central Park South, whose residents fought noisily to keep the rent-controlled apartments. Trump sought to drive them out of. The residents remain, ''but I don`t know how it`s a defeat, because the building is now worth 10 times more than it was five years ago.''

He thinks the city is wildly mismanaged. ''The rent-control laws,'' he continues, ''are incorrect and the big losers are the people of New York, because the city is getting such a tiny tax revenue. . . . Why should a designer like Arnold Scaasi, a multimillionaire who charges $20,000 per dress, be paying a very tiny rent?'' Scaasi, who has outfitted Trump`s own wife? ''He did, until I stopped him.'' (He told Ivana not to buy any more dresses.)

Speaking of what`s good for the city, Mayor Koch has regularly called Trump piggy. Trump has just as regularly branded the mayor a moron. ''It`s a disgrace,'' Trump says. ''I`ve enjoyed criticizing Koch because I enjoy the combat, but my New Year`s resolution is to work with him.'' Though he has threatened to spend millions for anti-Koch television spots this campaign year, he`s reconsidering that now.

Meanwhile, he has inspired a fresh crop of adversaries in his proposal to give Manhattan the ultimate booster shot, turning his 150-acre parcel of abandoned West Side railyards, 14 city blocks long, into Trump City, to include the world`s tallest building and largest shopping center, plus 7,600 luxury condos.

''The city desperately needs Trump City,'' Trump says evangelically. ''It needs the housing, the shopping, the jobs, and the billions in tax revenue it would produce over the years.''