‘Sexy grandma’ Sandi Feinberg lists UES townhouse for $18M

A historic Upper East Side townhouse that comes with its own salt-water pool is about to hit the market for $18 million. The five-story, neo-Federal-style manse at 17 E. 74th St. is owned by Sandi Feinberg, the “sexy” widow of the feisty philanthropist Herbert Feinberg who — at age 88 — sued Apple to stop…