Sen. John Glenn (D-Ohio), who formally announced his presidential candidacy last week, possesses as large an organization as any of the other five Democratic candidates, but suffers from the reputation of having no organization at all.

With little notice, Glenn has amassed a paid staff of more than 70--at least 60 in Washington and 11 more around the country--with a payroll of $100,000 a month, according to campaign manager William R. White. In size and payroll, this staff matches that of the front-runner for the Democratic nomination, Walter F. Mondale.

It now must show potential supporters and contributors that Glenn is capable of assembling a campaign team that is as effective as anyone else's.

"Things have changed," said White, Glenn's longtime top adviser. "The complaints about our organization may have been true before. But they are not true now."

White, 42, is the campaign's chief architect and manager whose political inexperience made him the chief target of initial criticism.

"I will acknowledge that we were not quite prepared for Ted Kennedy's withdrawal from the race last December ," White said. "We were elevated into the spotlight, and we weren't quite ready for that scrutiny. We were behind the curve. But we've made great strides."

Criticism of the Glenn organization had minimal impact on early fund-raising, White said, because 47 percent of the $1.1 million raised by Glenn in the first quarter of this year came from Ohioans willing to contribute no matter what.

"We've gotten the easy money," White said. "The perceptions of the quality of our organization will have a much greater impact on our ability to raise funds in the next three months than it did over the last three months."

Glenn's "strategy group" includes pollster William R. Hamilton, a southerner who is considered one of the best in the business and whose clients include Sens. Russell B. Long (D-La.) and Paul S. Sarbanes (D-Md.); and media adviser David Sawyer, who has produced commercials for such Democratic luminaries as House Speaker Thomas P. (Tip) O'Neill Jr. (Mass.), Sens. Christopher J. Dodd (Conn.), Thomas F. Eagleton (Mo.) and Daniel Patrick Moynihan (N.Y.) and Govs. Bruce Babbitt of Arizona and James B. Hunt of North Carolina.

The political director is Joseph Grandmaison, who organized New Hampshire for George McGovern in 1972, has since directed several campaigns in the Northeast and will run Glenn's political operation under White.

Treasurer Robert A. Farmer managed the finances of John B. Anderson's 1980 presidential campaign and for Gov. Michael S. Dukakis (Mass.) in 1982. Press secretary Greg Schneiders served in the Carter White House and in Carter's 1976 and 1980 presidential campaigns.

Scheduling and advance director Ted Rogers worked the Hubert H. Humphrey and Carter campaigns. Herb Heddon, who will be the chief delegate counter, was on the commission that drafted the Democrats' 1984 delegate-selection rules.

In Iowa, the first caucus state of 1984, Glenn's two top aides are Maureen Roach, former top aide to Rep. Tom Harkin (D-Iowa), and Don McDonough, who worked in the state for Carter in 1980.

In New Hampshire, the first primary state, Rick Jenkinson, a former aide to Rep. Norman E. D'Amours (D-N.H.), has been named state coordinator. Rick Sloan, former aide to Ohio's other senator, Howard M. Metzenbaum (D-Ohio) and a Kennedy campaign aide in 1980, has been named Glenn's coordinator for New England. There is no coordinator for the South, which Glenn views as his strongest region.

If, in September, Glenn's organization is up to speed, the widespread complaints of this spring will be forgotten. If not, they are likely to be recalled as harbingers of political doom.

Unlike the other candidates visiting the recent Massachusetts Democratic convention, Glenn did not arrive in time to do any politicking the night before the preferential straw vote. In fact, he missed most of his own reception for the delegates by arriving well after midnight.

Glenn was committed to a dinner honoring a longtime supporter in Youngstown, Grandmaison recalled, and was to pilot his plane to Massachusetts in time to be at his reception by 11 p.m. But the Youngstown dinner ran long, no surprise to veterans of political dinners.

"Did it make a difference?" Grandmaison said. "Yes. I have no question that if he'd gotten there by 11 p.m. he'd have come in third in the poll ahead of California Sen. Alan Cranston, who beat him by 1 percentage point . The other question is: is it worth it in the long run? I think no."

The next day, Glenn was the only candidate who did not attend a breakfast hosted by black and Hispanic delegates, even though his name was on the list of those to attend.

"He was never scheduled to go to the breakfast," Grandmaison said. "We wanted him to spend as much time as possible meeting individual delegates. We made that decision, right or wrong."

Another senior adviser said: "It was a gaffe."

When columnists Rowland Evans and Robert Novak wrote that Glenn had problems because of lack of endorsements in his home state, they cited three names, among them Rep. Edward F. Feighan (D-Ohio). That prompted Glenn to telephone them, something he had neglected for some time, and win promises of support.

Glenn had not bothered to telephone congratulations when freshman Feighan won his seat last November. Mondale called, as did other non-Ohioans who are candidates, and Mondale made several more calls, seeking Feighan's endorsement.