Republican presidential nominee Mitt Romney outraised President Obama by $21 million in the first half of October, taking advantage of a strong first debate and tightening polls to overtake the incumbent in the money race, officials said Thursday.

The influx of $111.8 million from Oct. 1 to Oct. 17 left Romney and the Republican National Committee with nearly $170 million in cash on hand, aides said. Obama and the Democratic National Committee said they raised $90.5 million during the same period and had $125 million in cash on hand.

The surge marks a turnabout for Romney, who had fallen behind the president in monthly fundraising since summer. Both sides have raised more than $1 billion each between the campaigns, political parties and super PACs, although Obama has brought in and spent far more through his campaign committee.

The hefty numbers suggest that neither side is likely to run into a cash crunch in the final 11 days of the race, as both campaigns continue to inundate swing states with broadcast ads, mailers and get-out-the-vote workers. The Obama team also reserved a $15 million line of credit.

The campaigns released the totals before a filing deadline of midnight Thursday at the Federal Election Commission.

Spencer Zwick, Romney’s finance chairman, said in a statement that the Republican’s economic plans “will bring much-needed change after the last four years and it is why we have seen such momentum and strong support from our donors.”

The Obama team said that more than 1.2 million people had given to the campaign during the first half of the month, including 207,000 new donors. “We’re making every effort to expand our donor base heading into the final stretch,” spokesman Adam Fetcher said.

Romney, who relies more heavily on large-dollar donations than Obama does, has kept up a steady pace of major fundraisers in the final stretch of the race, including a series of events in solidly red states this week held by Rep. Paul Ryan (Wis.), his vice presidential running mate. The GOP candidate’s finance team also held a conference call with major donors on Thursday aimed at drumming up even more money.

Restore Our Future, a super PAC assisting Romney, told the FEC that it had $24 million on hand on Oct. 17. The group received a combined $10 million from Las Vegas casino magnate Sheldon Adelson and his wife, Miriam. The duo have given close to $50 million to Republican causes this year.

American Crossroads, a major conservative super PAC, brought in $11.6 million, including a $4 million donation from Dallas billionaire Harold Simmons, who has given more than $22 million to Republicans this cycle.

Priorities USA Action, a super PAC backing Obama, raised $13 million in early October, including seven million-dollar checks from donors including financier George Soros.

The figures show that Romney and the RNC have widened their cash edge over Democrats this month, although some of their money is devoted to congressional races. But Romney could be limited in using all the extra cash effectively because the swing-state airwaves are saturated.

Republicans have vastly outspent Democrats in presidential ads in October, but the Obama campaign has been able to run more commercials by using discounted rates and other tactics.

Both campaigns went well beyond the fundraising pace set four years ago by Obama’s campaign, which together with the party raised $69 million in the first 17 days of October 2008. Obama and the Democrats raised just under $1 billion during the 2008 race, a record at the time.