Pop superstar Katy Perry is back on top of the Billboard Hot 100 chart with her latest single, "Part of Me," which becomes just the 20th single all time to debut at the chart's summit.  The song is the first single from Perry's deluxe reissue of "Teenage Dream," which spawned a total of five No. 1 hits itself, tying Michael Jackson's "Bad" for the most No. 1s on an album ever.  "Teenage Dream: The Complete Confection" is scheduled to arrive in stores March 27th.