A notoriously cranky ex-lawyer suffering from myriad mental and medical problems was slapped with a 45-day prison sentence yesterday for stashing more than $26 million in Swiss bank accounts.

Ailing octogenarian Kenneth Heller — who paid nearly $10 million in penalties in a bid to avoid the slammer — was told he needed to feel “the sting and the pain of some period of incarceration” despite its potential impact on him, his wife and a woman described as “his partner in a romantic relationship.”

“He had the opportunity at repeated junctures to think better of his actions,” Manhattan federal Judge Kevin Castel said.

Castel also ordered him to pay the maximum $180,000 in fines for his tax-evasion scheme.

BGolding@nypost.com