It has to come, and five years ago, it did. Abola Hassan Bakhtiar was stepping out of a bathtub. He slipped, fell and cracked his head. Three days later, he was dead of a cerebral hemorrhage.

He was either 100, 102 or 109. They weren't big on birth certificates around the 19th century prairies of Iran. Nor had any of his earliest neighbors lived as long. So no one could accurately say.

But this man will have no trouble being remembered. Perhaps Al Pacino should play him as a penniless, opium-addicted young nomad in rural Iran. Omar Shariff might take over as he comes to the U.S. well into adulthood to be educated for the first time. Maybe Godfather Brando would be best for the later years as wealthy surgeon, personal physician to the Shah's father and patriarch of a huge family.

But for 17 children and 27 grandchildren, no movie is necessary. Bakhtiar is their Superpop, and as his daughter Love said one recent afternoon, "We miss him every day."

She is one of three Bakhtiar daughters who live in the Washington area. One, Leele Bakhtiar, is a nursing student at Montgomery College-Takoma Park.

The teacher of Leele's health course was talking one day about long life and diet. The light bulb in her head swiftly switched on.

With the help of her sisters Love and Parveen, Leele worked up a synopsis of their father's diet for presentation to the class. It was mostly rice, lean meat and eight glasses of water a day. Now, if Alex Haley should be seeking a sequel . . .

He could choose worse. Abola Hassan Bakhtiar had a life his daughter Parveen calls "amazing, impossible to duplicate." Daughterly prejudice? Judge for yourself:

Born to nomads. Orphaned young. Never educated as a child. Worked his way up to become errand boy for the tribal chief.

Would probably never have gone further or elsewhere if an American Presbyterian missionary had not wandered along. Saw something in Bakhtiar. Said he'd take him back to the U.S. to shcool if he foreswore alcohol, cigarettes and opium. To the astonishment of his tribe, Bakhtiar agreed.

He arrived in New York in 1917. He was at least 45. He knew no English.He didn't have a cent.

He went to Missouri for high school, to Syracuse for college, then back to New York and Columbia University for medical school. All the while, he ran elevators and hauled trash to survive, and read Reader's Digest to learn the language.

His daughters say that marriage snuck up on him in storybook style. He was walking up some Columbia stairs with a friend. A 20-year-old nurse from Boise, Idaho, named Helen Jefferys was walking donw. "I will marry her," Bakhtiar is said to have said. Two weeks later, he proposed.

The couple's first child died as an infant. They moved to Iran in 1929. Then came:

Lailee, 48, a physician in Los Angeles.

Shireen, 47, an artist in Abdaon, Iran.

Parveen and Love, 46, the twins. Parveen McNair is a Chevy Chase artist. Love is a Hyattsville interior decorator and the former self-proclaimed "Queen of Haight-Ashbury." It was there she adopted the name Love, and served as a mother figure to the druggies at a hamburger shop she ran.

Jim, 42, the oldest son, was an All-America football player at the University of Virginia and is a psychiatrist in Iran.

Cyrus, a Washington pathologist, was next. He died on Christmas Day, 1974, in a boating accident on the Potomac.

Laleh, 31, is a religious scholar and author in Iran.

By the time of the birth of Laleh, World War II had ended. The couple was divorced, and Mrs. Bakhtiar came back to her native America and settled in Washington with the seven kids, where she worked as a realtor. Her husband, then beyond 70, stayed in Iran and took a new wife just beyond 20. Leele, 30, is the oldest of the ten products of that onion, and her youngest brother, now 12, was born when his father was no less than 93.

Of course there have been incessant jokes about that. Might the oldest act of them all be the real secret to longevity?

Parveen McNair says it was more a matter of exercising every day, showering twice a day and reading serious literature.

"My children read about sports heroes," she said. "Every morning, he would read 15th century poems."

Dr. Bakhtiar slept only about four hours a night, his daughters say. If he felt draggy, he would drink a glass of boiling water laced with two teaspoons of sugar. He claimed it did the trick.

He was also very regimented in his treatment of the children. He insisted that they be religious, study English and eat at home at mealtimes fixed in granite.

If he had a flaw, it might have been the way he favored his sons. "The white meat of a chicken was always for the sons," said Love.

Perhaps his greatest longevity secret was his attitude. "He just had all this love," said Mimi, 29, a daughter visiting Washington from Teheran. "He kept refusing to die. I don't believe he thought it could happen," added Love.

But the fateful bath came, and now it's a matter of memories. His daughter Leele had this one, which she included in the report to the health class:

"His Moslem faith preached that it is immoral to predict the future," she wrote. "He suggested that a real prophet is one who understands the present."