Anthony Weiner

Serial predator Anthony Weiner was sentenced to serve 21 months in a federal prison for enticing an underage girl and asking her to undress on Skype. Weiner, 53, broke down and cried when Manhattan federal Judge Denise Cote handed down her sentence on Monday.

“This was a serious crime. It’s a serious crime that deserves serious punishment,” the judge said, as Weiner dropped his head into his hand and wailed.

In May, the disgraced ex-Congressman plead guilty to one count of transferring obscene material to a minor.

His mother also wept openly on the bench behind him.

Weiner’s long-suffering wife, Huma Abedin, was not in court today.

In her book “What Happened,” Hillary Clinton described the emotional impact on her closest aide, Abedin, when she learned her husband was caught sexting a minor.

“When we heard this Huma looked stricken,” Clinton wrote. “Anthony had already caused so much heartache. And now this. ‘This man is going to be the death of me,’ [Huma] said, bursting into tears.”

Abedin filed for divorce earlier this year, but the couple still live together, and they walked together with their son to school 2 weeks ago. Weiner had to turn back when he got near the school because a registered sex offender can not be within 1,000 feet of a school.

Anthony Weiner

The feds said Weiner knew the 15-year-old girl was in high school when she contacted him on Twitter.com in January 2016.

“As January turned to February, their intermittent exchanges grew more lascivious,” Manhattan federal prosecutors told the judge.

In one explicit message, Weiner told the girl: “I would bust that tight pu–y so hard and so often that you would leak and limp for a week.”

He also sent the girl pictures of his genitals on self-destructing messaging apps like Kik and Confide.

As the courtroom cleared out, Weiner sat and cried as his legal team comforted him. His lawyers had asked Judge Cote to sentence him to probation.

Weiner is expected to turn himself in to begin serving his sentence on November 9.