Contrary to popular belief, money is not that tight -- in some circles at least.

Sen. Orrin Hatch (R-Utah) last night added $500,000 to his campaign coffers -- probably the largest amount ever raised by an individual candidate at one event -- for his 1982 reelection bid, in which he is unopposed. So far. And big business and the administration would like to keep him where he is..

Here's why:

First, Hatch is chairman of the powerful Senate Labor and Human Resources Committee, which, as Vice President George Bush politely reminded everyone last night, controls a lot of legislation and a lot of money.

And second, Hatch just about single-handedly derailed a labor-law reform bill in 1979, legislation proposed by the Carter administration and supported by organized labor. This made him very popular in big business circles and very unpopular with labor groups.

"Well, I'll tell you why I need all this money," said Hatch, oozing charm. "The night we won that bill by one vote I went to a party at John Sherman Cooper's house, and who was there in all his majesty but George Meany himself. He said, 'Orrin, we really respect you. We didn't think anyone could beat us on this bill, and I personally respect you. There are no hard feelings, but if it costs us $4 million dollars, we'll get rid of you in 1982.' "

Hatch's charm and demeanor belies his record as a senator who has fought organized labor every inch of the way since he got to Washington in 1976. He simply doesn't seem like a candidate someone would want "to get rid of." With his innocent good looks and apparently appreciative attitude ("I just can't believe all this interest in me," he kept repeating), he seemed to make every last lobbyist who showed up with $500 at the Hyatt Regency feel like his best friend. He must have pumped 300 hands, looking everyone straight in eye and telling one and all, "We won't forget you."

"He's a wonderful man," said Anna Chennault, who, along with Betty Southard Murphy and Charlene Cracraft, hosted the party. "Be careful how you refer to me," Chennault instructed a reporter. "I'm a business executive, not a Washington hostess. I just do fund-raising for my friends."

Among the other guests were Republican Sens. Harrison Schmidt (N.M.), Strom Thurmond (S.C.), Paula Hawkins (Fla.), Jake Garn (Utah), the vice president and Barbara Bush and National Security Adviser Richard V. Allen, who managed to whisk the Bushes to a reception next door for Faith Ryan Whittlesey, who was sworn in as ambassador to Switzerland yesterday.

"It'll only take a minute," assured Allen to the Bushes.

"Really, we've got to go. We're getting up early," said Bush, looking slightly exasperated.

"Do we know her?" asked Barbara Bush.

"She was with the campaign," said Allen.

They went.

Across the hall:

"Ambassador," called the vice president grinning widely, entering the room.

"We're so proud of you," said Barbara Bush, kissing her.

Meanwhile, back in the Ticonderoga Room, the lobbyists outnumbered the politicians. The Associated Builders and Contractors had 20 people there -- probably the most of any organization. And they wanted everybody to know it.

ABC lobbyist No. 1: The Gofer. "Excuse me, are you a reporter? Would you mind coming over and talking to my boss? He'd like you to talk to our president who's here from Houston. We just think it would be nice for him to talk to the press."

ABC lobbyist No. 2: The Boss. "Hi. We thought you might like to talk to the president of the group that gave the most money tonight . . . In excess of $100,000."

ABC lobbyist No. 3: The Big Boss: "I know Orrin and I'm a personal friend of George Bush ," said Franz June of Houston. "Orrin is a young, bright senator in favor of the free enterprise system, and that's what we support. He's a good man."

ABC lobbyist No.4: The Bystander. "Quite frankly, I'm just here to kill a few hours before my wife gets out of her law class. I really don't know much about what's going on here. There was an extra ticket."