* Obama raised $181 million, set 2012 record
* Romney does not control large portion of money
* September saw release of '47 percent' video
* Monday kicks off big Romney donor gathering in New York
WASHINGTON, Oct 15 (Reuters) - Republican presidential challenger Mitt Romney and his allies raised $170.5 million in September, the campaign said on Monday, falling just short of the 2012 fundraising record set last month by Democratic rival President Barack Obama.
Republicans began October with $191.2 million in cash on hand - money ready to be spent on advertising, get-out-the-vote efforts, staff, offices, rallies and other campaigning in the weeks before the Nov. 6 election. Much of the haul, however, was not likely to directly benefit Romney's election bid.
Obama and the Democratic National Committee already have reported raising $181 million in September, the best mark so far in the most expensive presidential election campaign in U.S. history. They did not disclose how much they had left in cash on hand.
September was the second consecutive month in which the Democrats out-raised Romney's team after three months of the Republicans leading the way in fundraising.
It was also one of the toughest months for Romney: his position weakened in the polls first as a result of the new focus shifting to the Democratic Party Convention and then to a secretly filmed video that showed him calling 47 percent of Americans who receive government funds "victims."
Romney regained footing earlier this month when he delivered a strong performance against Obama in the first presidential debate on Oct. 3. Campaign officials said the debate kicked up donations and helped the Republican candidate gain on the incumbent in the polls just weeks ahead of Election Day.
"With less than one month left, we will continue the hard work of raising the resources to ensure that Mitt Romney and Paul Ryan can win in November and bring real change to the American people," said Spencer Zwick, Romney's finance chairman.
Obama has since regained a slim lead in the tight race. The Reuters/Ipsos daily tracking poll on Monday showed him at 47 percent compared with Romney's 45 percent.
"This race is tied," Obama said in an email to supporters asking for last-minute donations on Monday. "What we do over the next 22 days will determine not just the next four years, but what this country looks like for decades to come."
ROMNEY'S CASH THAT ISN'T HIS
Since Romney became the party nominee in April, he and the RNC have fundraised together, pulling cash into their separate funds as well as a joint account known as the "Romney Victory."
Because the fund's disclosures are released quarterly, much of the Republican cash had been sitting under wraps until Monday, when new filings showed that in the third quarter of the year, the joint fund raised $235.2 million - beating the second quarter haul of $140.3 million.
But most of that cash - at least $214.4 million - does not belong to the Romney campaign: A donor can only give $35,800 to benefit a candidate and the party and at most $5,000 of that can go into the candidate's coffers.
Anything given beyond that amount to the Romney Victory fund is slated to benefit state Republican parties, the National Republican Senatorial Committee and the National Republican Congressional Committee.
Reuters calculations showed that of all the money brought into the Romney Victory fund, only as much as $161.1 million belongs to the Romney campaign, while at least $54.6 million is booked for state parties and congressional committees.
Obama and the DNC also have a joint "Victory" fund but the Obama campaign keeps the vast majority of its cash under its own control - which affords it more flexibility in deciding how and when to spend it.
DONORS AND FUNDRAISERS
Romney's financial operation has relied heavily on large checks written by wealthy supporters, in contrast to the Obama campaign, which has been aggressively courting such donors as well but relies mostly on smaller contributions.
The Romney campaign said it received more than 1 million donations in September in checks of less than $250, which were responsible for a total of $43.2 million.
Of all the cash received, 93 percent of all donations were of $250 or less, the campaign said. That means some $127 million was raised through less than 7 percent of the donations.
The Romney campaign continued to court large donors this week as some of the most influential of them gathered at a luxury hotel in Manhattan for a three-day "fall retreat" that started Monday.
The gathering was expected to include "special guests" including former New York Mayor Rudy Giuliani, real estate magnate and reality TV star Donald Trump, and Oklahoma oilman and Continental Resources CEO Harold Hamm.
Others expected to attend include Charles Schwab Corp CEO Charles Schwab and Jimmy John's sandwich franchise CEO Jimmy John Liautaud, according to an invitation posted by the Sunlight Foundation, a nonpartisan group that seeks more transparency in campaign finance.
Major fund-raisers and donors were scheduled to attend election strategy meetings with top Romney campaign staff and mingle with vice presidential candidate Paul Ryan.
Romney had originally planned to join in, but changed plans on Monday to prepare for the second presidential debate against Obama on Tuesday night at New York's Hofstra University.
Obama's campaign, which holds the all-time fundraising record for its 2008 efforts, said it had held its last fundraising event last week. In 2008, Obama's campaign and the DNC together brought in $193 million in September and came close to raising $1 billion overall.