Lindsay Lohan Does Penthouse

Lindsay Lohan is NOT slumming it in NYC ... quite the opposite, she's livin' pretty in a penthouse.

There are reports out Lindsay is living at her mom Dina's Long Island home, but it's not true. We've learned she's staying at her friend's SoHo apartment. The friend is letting Lindsay stay there rent free until she finds a place of her own.

And the friend hasn't set any deadlines for moving.