Updated at 12:46 p.m.

In the first 41 days of his run for the White House, Sen. Bernie Sanders (I-Vt.) raised $18.2 million, his campaign announced Tuesday.

The money came in the form of nearly 900,000 contributions from 525,000 individual donors, according to campaign manager Faiz Shakir.

"Supporters have shown up big time for this campaign," he told reporters on a campaign conference call. "Huge, you would say."

In addition to the $18.2 million in new contributions, Sanders brought to the race $14 million from other campaign accounts, including his Senate reelection fund and his 2016 presidential campaign kitty. He spent a little over $4 million in his first weeks in the race, leaving him with roughly $28 million cash on hand.

According to senior adviser Jeff Weaver, Sanders’ strong fundraising start will enable him to campaign in states he had to write off during his first run for the presidency.

“While we had to, in 2016, make choices about where we could compete … this campaign will have the resources and the volunteer, grassroots strength to compete in every single state in the primary process,” said Weaver, who served as campaign manager four years ago.

Sanders’ announcement came soon after Sunday's quarterly Federal Election Commission fundraising deadline. Because campaigns are not required to publicly disclose details of their fundraising and spending until later this month, it's impossible to verify Sanders' self-reported numbers, nor to compare them to those of his rivals.

Only two others have announced their fundraising figures so far: Sen. Kamala Harris (D-Calif.) reported raising $12 million from 138,000 individual donors in the first quarter, while Mayor Pete Buttigieg of South Bend, Ind., said he picked up $7 million from 158,550 donors.

The Sanders campaign held no fundraisers in the first quarter, according to Shakir, and raised nearly all its resources online — mostly from small-dollar donors. The average contribution amounted to $20, he said, and 88 percent of the total money raised came from those contributing less than $200.

"I think they're playing for the long haul here," Shakir said of those donors. "A lot of folks [are] thinking that this is a marathon, not a sprint."

Twenty percent of the campaign’s contributors had not previously given money to Sanders, and a majority were under 39 years old, according to Shakir. “That is unprecedented,” he said.

Sanders fell short of his goal to secure 1 million donations before Sunday. Shakir conceded that there had been “a lot of internal discussion” about whether to announce such an “ambitious goal” that the campaign might not be able to meet. But, he said, “inspiring our movement” was worth it.

“There’s no shying away from 900,000 donations,” Shakir said. “I’m sure all the other campaigns would love to be in that posture.”