The preliminary number released Tuesday comes with a couple of asterisks.
The final number could grow because the administration is offering a grace period for people who started applications — but couldn't finish them — before last Sunday's official deadline. They have until February 22, this coming Sunday.
Also, Democratic lawmakers are pressing Obama to grant a second chance to sign up for uninsured people facing tax penalties.
But the final number could shrink if consumers who've enrolled for 2015 coverage don't follow through by paying their share of premiums.
Last year, 8 million people signed up initially. But by fall, 6.7 million were left.