REPUTED Genovese crime boss Vincent (The Chin) Gigante, who occasionally walks around his Sullivan St. haunts in a bathrobe and slippers, must be worried that the feds are closing in, again.

FBI agents who've been chasing him around for more than five years have long maintained that Gigante, 60, goes into his crazy act whenever he's concerned that he may be close to indictment.

For the 25th time In the last 20 years, Gigante has been institutionalized for schizophrenia, according to the Rev. Louis Gigante, the South Bronx priest who insists that his brother has nothing to do with organized crime.

"He was hallucinating to the extent that we couldn't hold him," Gigante told Daily News reporter Bob Gearty.

Rev. Gigante, who started proceedings earlier this year to have The Chin declared incompetent, declined to name the hospital, but said his brother was committed by his 87-year-old mother and an other brother.

Gang Land's not looking to start any more trouble for Gigante, but we hear that the IRS has started poking around, too.

G IGANTE'S mental status certainly doesn't have any ill effects on his card playing abilities -- at least when he plays with wiseguys at his Greenwich Village base of operations, the Triangle Social Club on Sullivan St.

The Chin never loses there, says former capo Vincent (The Fish) Cafaro.

In recent testimony at the federal racketeering trial of mobster Federico (Fritzi) Giovanelli, Cafaro told of seeing a game which was typical of all card games.

As soon as the cards were dealt, The Chin looked at his hand, and said: "Rummy."

Immediately, without even glancing at Gigante's cards, the players threw down their cards for the next deal.