50 Cent -- I'm So Bad Off I Even Owe My Grandfather Money!

50 Cent isn't really broke -- we know that -- but he's sure making it look like he is ... he just gave the bankruptcy judge a list of his many creditors, and Curtis Jackson Sr. is among them.

According to the docs -- obtained by TMZ -- 50 owes grandpa $1,737.33. But that's just the tip of a $26 million debtor's iceberg.

50 also owes $137,880 to Bentley, $64,909 to American Express and, oh yeah, 2 court judgments totaling more than $23 million. And there's more -- that's just boring debt.