It'll crack the charts and remain the #1 song for all of eternity. Katy's majestic songwriting skills, and Dr. Luke's producing innovation deserve none the less. All bow to the Queen of Pop Katy and her #1 single.
I'm gonna go with 6-7 weeks. She'll easily take next week, the week after, then Britney may put up some competition (unlikely), then she should be able to take three weeks after until Eminem starts building up and she releases her second single right before her album. I can't at people saying less than 5.