Katy Perry's 2010 hit "Teenage Dream" tops the 4 million mark in digital sales this week. It's her sixth song to reach this plateau, which is more than any other artist. Lady Gaga, Eminem, Rihanna and Lil Wayne have each amassed three 4-million-sellers (counting featured credits for Rihanna and Lil Wayne). Here are Perry's songs that have reached this plateau, and their current sales tallies, courtesy of our friends at Nielsen SoundScan: "Firework" (5,075,000), "Hot N Cold" (5,066,000), "California Gurls" (featuring Snoop Dogg, 5,056,000), "E.T." (featuring Kanye West, 4,838,000), "I Kissed A Girl" (4,155,000) and "Teenage Dream" (4,003,000).
So happy right now 
This is happening 
