"World," co-written by Ke$ha, concurrently starts at No. 68 on Radio Songs with 16.8 million out-of-the-box audience impressions on 145 stations, according to Nielsen BDS.
Lady Gaga's "Born This Way" banks a fourth week -- its entire chart life -- atop the Hot 100. The song is the first to begin at No. 1 and remain on top for as many as four frames since Aerosmith's "I Don't Want to Miss a Thing" (also four) in 1998.
Four other songs have launched with as much lasting fanfare: Mariah Carey's "Fantasy" (its first eight weeks, 1995); Carey and Boyz II Men's "One Sweet Day" (16, 1995-96); Puff Daddy (as he was then credited) and Faith Evans' "I'll Be Missing You," featuring 112 (11, 1997); and, Elton John's "Candle in the Wind 1997"/"Something About the Way You Look Tonight" (14, 1997-98). "Born" is the only such song to achieve the feat in the digital era.
Two other notable movers shake up the Hot 100's top 10.
Following the premiere of the "On the Floor" video on the March 3 "American Idol" episode, new judge Jennifer Lopez's first top 10 as a lead artist since 2003 jumps 9-5 as the Digital Gainer in its second chart week. Sales swell by 31% to 223,000 downloads sold.
Jennifer Lopez's 'On the Floor' Video Premieres on 'American Idol'
"Floor" is the first song to debut in the Hot 100's top 10 and increase in position and chart points in its second week since P!nk's eventual No. 1 "So What" rose 9-3 in its second frame the week of Sept. 13, 2008.
Two spots below Lopez, Ke$ha's "Blow" blasts 11-7. The second single from "Cannibal," following the No. 1 "We R Who We R," rises 10-6 on Digital Songs (164,000, up 27%). Ke$ha has now sent all six of her singles as a lead artist into the Hot 100's top 10. She also reached No. 9 last May as a guest on 3OH!3's "My First Kiss."
Ke$ha Kills James Van Der Beek in 'Blow' Music Video
Rounding out the top 10, Cee-Lo Green's "F**k You (Forget You)" claims Airplay Gainer honors and holds at No. 2 for a third consecutive week. The song pushes 6-4 on Radio Songs (97 million in audience, up 20%).
Rihanna's "S&M" surges 5-3 on the Hot 100, passing P!nk's "F**kin' Perfect" (4-4), and Bruno Mars' "Grenade" descends 3-6.
Katy Perry places two songs in the top 10 for a second consecutive week. "E.T.," featuring Kanye West, holds at No. 8, rising 57-38 on Radio Songs (33 million, up 66%), and "Firework" falls 6-10.
In between Perry's songs, Enrique Iglesias' "Tonight (I'm Lovin' You)," featuring Ludacris and DJ Frank E, slips 7-9.
Eight additional debuts join Spears' "World" in entering the Hot 100, led by Foo Fighters' "Rope" (No. 70), the No. 1 title on Rock Songs.
Ousted 2011 "American Idol" hopeful Chris Medina's "What Are Words" bows at No. 83. Proceeds of the song's sales benefit a fund established to assist Medina's fiancee, Juliana Ramos, who suffered a brain injury.
'American Idol's' Chris Medina: Jennifer Lopez's Breakdown Was 'Touching'
After she co-hosted "The Oprah Winfrey Show" March 1, 10-year-old Willow Smith re-enters her debut hit, "Whip My Hair," at No. 86 (25,000 downloads, up 41%) and charts her follow-up, "21st Century Girl," at No. 99 (23,000 first-week downloads).