That's 1 million more than congressional scorekeepers had initially projected.
Obama also says 35 percent of those who signed up are under the age of 35. Enrolling substantial numbers of younger, healthier Americans is crucial for the law's success.
The figures represent positive signs for Obama's health care law. After HealthCare.Gov debuted disastrously last year, expectations were lowered that the administration would be able to enroll enough people.
Obama says, quote, "This thing is working."
Obama says premiums will rise in the future, but are rising more slowly than in past years thanks to the Affordable Care Act.
Obama spoke during an unannounced appearance in the briefing room of the White House.