Other evangelists come and go, but Billy Graham, with a public longevity that surprises even him, endures.

At age 62, Graham, confidant of businessmen, movie stars and presidents, whisks around the world on a dizzying schedule of international crusades and engagements with the makers and shakers of government, business, the church and academic life. But he still calls himself a country preacher, and wonders about his success.

"I would have thought that my work would be declining by now," he said recently. "Most evangelists, like Billy Sunday, Dwight L. Moody, preached for 10 years and that was about all." In contrast, Graham continues to have far more requests for his massive citywide evangelistic crusades than he can begin to handle.

"There are more cities than ever before begging me to come," he said. Moreover, his crusades, one of which is scheduled for Baltimore next spring, are bringing "the greatest response in my lifetime," he said. In his last two crusades, he said, a higher proportion of the audience made "decisions for Christ" and more of these repentant ones were people without any previous ties to the church. One of the perennial criticisms of Graham's crusades has been that so many of his converts are people who are already church members.

Church historian Martin Marty of the University of Chicago, who marches to a different theological cadence than Graham, nevertheless attributes to him a major role in American church life. "Billy Graham ranks in the top three or four evangelists of American church history," Marty said, bracketing him with such giants of the 18th and 19th centuries as George Whitfield, Jonathan Edwards and Charles G. Finney.

Graham's professional survival is the more remarkable, Marty continued, since "celebrity status and religion don't mix at all well. There is something about the style of life of the religious celebrity, with its groupies and all, that great numbers usually end up either in financial or sexual scandal."

Over th years Graham has repeatedly scored high in "most-admired" and general popularity polls; two years ago he outpolled God in "achievement in religion" in a poll of high school students.

While questions were raised several years ago about the failure of the Graham organization to make full public disclosure of records of one of its special funds, subsequent investigations disclosed no substantive impropriety. "With Graham, there's not a lot of muck to rake, else [Marshall] Frady would have raked it," Marty said. Two years ago Frady wrote a detailed and generally unflattering biography of Graham.

Graham's policy of turning the other cheek to criticism has tended to defuse his critics, Marty believes. "Those of us who are critical of Graham's theology know that he's not mean, so you don't let yourself get mean" in criticizing him.

A major reason for Graham's success, Marty said, is the evangelist's policy of cooperating with local churches whereever he conducts a crusade, instead of going it alone, as do most contemporary evangelists. The big difference between Graham and traditional evangelists, Marty said, "is that he has an impeccable relationship to the churches." "He doesn't open a crusade unless the Catholic bishop is onstage with him the first night, and the Methodist bishop, and all the others," Marty said.

Graham is in Washington this weekend for a board meeting of the evangelistic association that bears his name and to fulfill a promise to longtime friend Sen. Mark Hatfield (R-Ore.) to preach Sunday morning at Georgetown Baptist Church.

Graham has been on a first-name basis with the last six presidents. The tradition will continue in the Reagan administration.

He and President-elect Reagan have "been friends for about 30 years," he said. "We met through his mother-in-law, Mrs. Davis. I was playing golf in Phoenix and she said to me: 'You should know my sin-in-law, Ronald Reagan.' I said, 'You mean Ronald Reagan the movie star?' She said 'yes' . . . Then, I think it was in the fall of 1952, he [reagan] and I were speaking in Dallas at a benefit. I think it had something to do with a retirement center in California for motion picture people."

Graham said he knows Vice President-elect George Bush "very well. We were on holiday together in Mexico two years ago. My wife and Barbara Bush are very close."

With such close ties, did Graham anticipate frequent invitations to the Reagan White House? He answers: "Well, from what I read, there's going to be a change of style at the White House" -- here a pause and a laugh -- "and I'm a country preacher."

Graham has not been invited to take part in the Reagan inaugural next month, as he did in the Johnson and Nixon inaugurations. But the Rev. Donn Moomaw, Reagan's pastor from California, who will give both the invocation and the benediction was once a member of Graham's evangelistic team.

Ever since Graham's close association with Richard Nixon earned him the unwanted reputation as the chaplain of the Nixon White House, the evangelist has been at pains to put a little distance between himslef and whatever administration is in power. Just before the election four years ago he took the unusual step of disassociating himself from a widely publicized prayer rally in Dallas when it became clear that the prayers would likely turn into petitions for devine deliverance from a Democratic president.

What, then, did he think of the political hit lists and politicking of the Moral Majority and the others of the new right? Choosing his words carefully -- Graham has a policy of never criticizing a fellow clergyman in public -- he said: "I would hate to see either right-wing or left-wing groups using evangelical Christians for political ends. In the long term, it will dilute the Gospel that we preach."

Graham said he does not believe that the religious right had a "a decisive impact" on the election results. "There was a general mood for change," he said. "There were problems that were beyond any president's grasp -- the price of oil, problems in the Middle East, the hostages . . . The mood of the country is for change. You know, we haven't had a two-term president since Eisenhower."

Significantly, perhaps, Graham made no mention in his listing of national problems of any crisis in morality, the far right preachers' favorite analysis of the national mood.

At 62, Graham's thoughts are on his work and not retirement. "I don't think too much about it," he says of the latter. "Physically I am in good shape. I can keep on what I've been doing for five or six years." What he's been doing keeps him constantly on the go, spending nearly half his time overseas in crusades and conferences with a truly incredible range of people.

Early next year, for instance, he heads for Poland for conferences at the University of Warsaw, then to Hungary where he conducted a crusade three years ago. Then he'll return by way of Southern Europe and England, by way of Southern Europe and England, where he is scheduled for a public debate with the former Archbishop of Canterbury, Dr. Arthur Michael Ramsay, on "The Mission of the Church." "I don't really know what we will debate about since we're such good friends and agree on so many things," Graham said.

Even in retirement from such scheduling, Graham's plans don't include much time on the front porch of his idyllic North Carolina mountaintop retreat. "I would like more time to write," he said. "Then I'd like to spend time at interdenominational seminaries, sharing my life and experiences."