It’s the diva’s fourth solo No. 1 — and fourth studio set to top the list. She’s only the third act — and second woman — to see their first four studio albums debut atop the Billboard 200. Britney Spears did it with her first four between 1999 and 2003 while DMX’s first five all started at No. 1 between 1998 and 2003

“4′s” sales launch is lowest of her four releases: 2008′s “I Am … Sasha Fierce” entered with 482,000; 2006′s “B’Day” bowed with 541,000 and 2003′s “Dangerously In Love” started with 317,000.

Of course, “4″ is thus far lacking a smash hit single, which could help explain the album’s softer entry. Its lead track, “Run the World (Girls),” peaked at No. 29 on the Billboard Hot 100 — the first time the first single from a Beyonce studio set has missed the top 10.

Still, “4′s” bow is pretty big for 2011. It marks the third-largest sales week of the year, after the No. 1 bows of Lady Gaga’s “Born This Way” (1.1 million) and Adele’s “21″ (351,000).

Also arriving in the top 10 this week is rapper Big Sean’s debut album “Finally Famous” (No. 3 with 87,000), Selena Gomez & the Scene’s third set “When the Sun Goes Down” (No. 4 with 78,000), David Cook’s sophomore effort “This Loud Morning” (No. 7 with 46,000) and Scotty McCreery’s Wal-Mart exclusive five-song (and $5) EP “American Idol Season 10 Highlights” (No. 10 with 40,000).