Congratulations to Katy Perry! Her latest single, 'Part Of Me,' is on its way to having the biggest debut numbers since Lady Gaga's 'Born This Way.'
Billboard reports that the single, released digitally on Monday, Feb. 13, is expected to sell between 400,000 to 420,000 downloads by tomorrow. If it sells as much as expected, it will be Perry's biggest debut ever (even bigger than the inescapable 'California Gurls' and 'Teenage Dream'). It will also be the highest opening week for any act since Mother Monster, whose 'Born This Way' moved 448,000 copies its first week.

Both Perry and Gaga released their singles coinciding with their Grammy performances. Gaga released 'Born This Way' on Feb. 11, two days before her performance at last year's Feb. 13 show. Perry will move roughly the same numbers in seven days (her performance was Feb. 12) as Lady Gaga did in three.

Also helping Perry move her new music? Her divorce. The single is the first from a series of new tracks on her 'Teenage Dream: The Complete Confection' re-release, and the kiss-off anthem clearly has reworked lyrics aimed at ex Russell Brand. Living well is the best revenge -- and a No. 1 single that the world can't stop singing ain't bad, either.