Informed sources tell TMZ ... Russell and Katy did NOT have a prenup. As a result, everything they earned during their 14-month marriage is community property -- which means they're each entitled to 50% of the pot.
Katy made $44 million between May, 2010 and May, 2011 -- according to Forbes. The couple married in October, 2010, so Russell could have scored a fortune if he exercised his community property rights.
And let's face it we all know Russell made much less than that.
As for Katy, well she's doing pretty good -- $44 million in the last year, that's like Mitt Romney rich! If only he could sing like her!