Former Gov. Andrew M. Cuomo and Zohran Mamdani, a progressive state lawmaker from Queens, will announce strong fund-raising numbers in the New York City mayoral race on Monday as they push to unseat Mayor Eric Adams.

Mr. Mamdani has raised more than $840,000 over the last two months and has more than 16,000 total donors, his campaign said. It is a surprisingly good showing for a candidate who was not well known to New Yorkers until recently, but who has attracted attention for his use of social media and vocal opposition to the Trump administration.

Mr. Mamdani said in an interview that his campaign had momentum because he was focused on addressing the high cost of living in the city.

“We have run a campaign that speaks directly to the working class, and I think that’s resonating,” he said.

The campaign fund-raising deadline on Monday will provide a snapshot of the race roughly 100 days before the Democratic primary in June. Mr. Adams is running for a second term while confronting record-low approval ratings.

Mr. Cuomo, who has led in polls, raised $1.5 million from more than 2,800 donors in 13 days, his campaign said. He expects to receive public matching funds after raising $330,000 in eligible funds from 1,700 donors who live in the city.

His donors include Geoffrey S. Berman, the former United States attorney in Manhattan who was fired by President Trump in 2020; Mr. Cuomo’s former wife, Kerry Kennedy; and Jessica Seinfeld, the cookbook author and wife of the comedian Jerry Seinfeld.

“I’ve been humbled by the depth and breadth of the outpouring of support we’ve received upon entering this race,” Mr. Cuomo said in a statement. “New York is the greatest city in the world, and those who live here deserve a New York that is better, stronger, safer and more affordable than the New York we have today.”

Two other leading Democrats announced their fund-raising totals on Sunday. Brad Lander, the city comptroller, raised $225,000 during the recent filing period that ran from January to March.

“These results show that New Yorkers are hungry to end the Adams-Cuomo nightmare of endless scandal and corruption, and replace it with strong, honest leadership,” he said in a statement.

Adrienne Adams, the City Council speaker who announced her campaign on March 5, raised $128,000 in five days. Her campaign said she had not yet met the threshold for the city’s generous public matching funds program, which awards $8 for every dollar donated by a city resident, up to $250 per person.

Ms. Adams, who is not related to the mayor, visited Bethany Baptist Church in Brooklyn on Sunday and told reporters that she would catch up on fund-raising. She said that even though Mr. Cuomo might be leading in the polls, he had “very high” unfavorable ratings.

She told the congregation that New Yorkers are “tired of the drama” and “tired of the trauma,” an apparent reference to Mr. Adams’s legal and political troubles. Ms. Adams said she had received phone calls from out-of-town relatives asking what was going on in New York.

“We don’t have to continue to be a city of embarrassment,” she said.

Several campaigns have already qualified for public matching funds, including those of Mr. Lander and Mr. Mamdani. A candidate must raise at least $250,000 and receive contributions from at least 1,000 donors who live in the city to qualify.

Mr. Adams, who is facing federal corruption charges, was denied public matching funds in December. The city’s Campaign Finance Board ruled that he was not eligible because of the conduct outlined in his indictment, a decision that prevented him from receiving as much as $4.3 million.

Several of the mayor’s longtime allies have endorsed Mr. Cuomo. Mr. Adams has not begun to campaign seriously, though he insists he is running for re-election.

Mr. Cuomo, who resigned in 2021 after a sexual harassment scandal, is arguing that he is the most experienced candidate and the one who can get things done. He has denied the harassment allegations and challenged his accusers in court.

Mr. Mamdani, who released plans to freeze rents and to make buses free, has risen in the polls. A recent Quinnipiac University poll showed him in third place after Mr. Cuomo and Mr. Adams.

A video of Mr. Mamdani confronting Tom Homan, President Trump’s border czar, in Albany last week went viral. His campaign said he raised nearly $250,000 in the day or so after the video was posted.

Another social media post by Mr. Mamdani was widely skewered for his breach of subway etiquette. A photo showed the candidate placing a large burrito and a side of salsa on a subway seat late one evening while holding a fork and knife over them.

But Mr. Mamdani, who is Muslim, took the ridicule in stride, saying that the photo reflected his busy campaign schedule during Ramadan.

The photo, he said, expressed the reality of “fasting while campaigning and not always having a place to break your fast except the train you’re taking from one event to the next.”

Sean Piccoli contributed reporting.