The randy rabbi is a deadbeat dad.

Marc Schneier — the founding rabbi of the tony Hampton Synagogue in Westhampton, who was forced out in 2016 after he cheated on wife No. 5 with the woman who would become wife No. 6 — owes $64,594 in unpaid child support, according to records obtained by The Post.

As of Sept. 15, 2018, the State of Florida has ordered the father of two to start forking over $5,000 a month for his 19-year-old son, Brendan.

According to the young man’s mother, artist Toby Gotesman Schneier (wife No. 3), in the 2005 divorce Schneier was ordered by New York state Supreme Court to pay $4,200 a month, increasing by $200 each year, until Brendan entered college. At that point, the amount would be cut in half, to $3,200, until Brendan is 22 or graduates college. The money is intended to cover his living expenses.

But Gotesman Schneier says that Schneier decided, without court intervention, to reduce the amount even further once Brendan enrolled in college.

It’s gotten to the point where Brendan, a sophomore at the University of Miami, told his mom a few weeks ago, “‘I can’t even afford food.’ He had tears in his eyes,” said Gotesman Schneier, 58, who was divorced from Schneier in 2005, after 12 years of marriage.

In December, the state of Florida requested that New York state get involved in the case. It has also asked the IRS to intercept any federal income tax refund ­Schneier might receive and for the State Department to deny his passport renewal.

That would be a big blow to the self-styled statesman, 60, who regularly globe-trots in the name of fostering Jewish-Muslim relations. This past week, he was in Abu Dhabi alongside Pope Francis and other interfaith religious figures at the Global Conference of Human Fraternity.

A spokesman denies that Schneier owes any back child support, saying: “The case in Florida has been closed for some time. These allegations are ridiculous.”

But the Florida Department of Revenue’s Web site shows the case is still active.

Barbara Zimet, a congregant acting as Schneier’s lawyer, sent a letter to Gotesman Schneier in August 2017 that read, in part, “It is crystal clear … that our client has been overpaying the monthly basic child support payments since July 2011.” It said he would begin paying $2,146 each month.

“You can’t legally go against a court order,” said Gotesman Schneier, who lives in Fort Lauderdale, Fla.

“As far as our relationship, there’s not much of one,” said Brendan of his father. “I’m just fine with that.”

Still, he is hurt by what he sees as stinginess.

“It doesn’t happen every day that a rabbi has a $3 million Hamptons house,” said Brendan of his father, who keeps a city apartment in 1 Sutton Place, designed by Rosario Candela.

“There’s no excuse for not paying [child support] — all he has to do [to save some money] is not go to Cipriani.”

Schneier 30 years ago founded the Foundation for Ethnic Understanding, which promotes Muslim-Jewish relations.

The foundation’s most recent available tax filing, from 2016, reveals a personal salary for Schneier of $395,303, plus additional compensation of $44,000.

Schneier is also said to still be making full child-support payments for his 4-year-old daughter, Brooke, whose mother is wife No. 5, Upper East Side resident Gitty Leiner. But according to a friend of Leiner’s, “He’s not involved like a normal parent is.”

“He’s not the greatest father to her whatsoever,” said Brendan, who added that his young half-sister has been to visit him in Florida.

A well-placed congregant told The Post that Schneier’s seeming indifference toward Brooke was the final straw for members of the shul willing to overlook his romantic indiscretions, adding that rumors swirled that he’d go several months without seeing his daughter.

(Schneier’s rep had no comment on the relationship with Brooke.)

Brendan, who said “everything I am today I owe to my mother,” adds he is nothing like his dad.

“The difference between my father and I is that I actually love women,” the teen said.

“Women are not objects.”