Soul Ja Boy Has More Money, If God Was Chief Keef

According to TMZ, Soulja Boy is 23 years old and has more money in his sweat pants than you'll see in a year ... which he happily showed off to our pretty jealous photog.

Soulja was strolling' around in LA Saturday when TMZ camera guy asked if he was still celebrating his birthday  -- at which point Soulja went all Chief Keef on him and flashed some bills.

By "some" bills -- we mean STACKS and STACKS and STACKS of cash. Possibly more than Keef.

As for why he walks around so pocket-heavy -- they let him explain. It sort of makes sense.