Allen Iverson -- Atlanta Mansion to Hit Foreclosure Auction

Former NBA star Allen Iverson's about to lose his massive Atlanta mansion -- because the bank is gearing up to sell the house at auction next week, TMZ has learned.

Iverson purchased the home back in 2010 for $4.5 million -- but according to official records, he defaulted on his mortgage and the bank foreclosed. Now, the home is set to be sold at auction on December 4th ... along with all the crap inside.

Iverson's currently going through a nasty divorce with his estranged wife, and he's famously been dealing with money problems ... including a nearly-million-dollar debt to a Georgia jeweler.

A.I. still has a chance to save it if he comes up with the cash before auction time ... but the clock's ticking ... fast.