Here's why a billionaire Arab prince -- owner of a Boeing 727 and estates in Riyadh (Saudi Arabia), Paris, London, Cannes and Leesburg --spends all of his days trying to get money from other people:

"It's not the money," Prince Talal bin Abdul Aziz Al-Saud said at a Hirshhorn Museum reception in his honor last night. "It's a matter of making American people aware of the misery of children in the Third World . . . Your people have to know."

But the money--his wealth is estimated at $6 billion--certainly helps.

Since 1980, Talal, 52, third in line to the Saudi throne, has traveled the world in his private jet raising more than $50 million in contributions for UNICEF, the United Nations' organization for children's education and nutrition projects.

"I don't know how I got started in this," he said. "Princess Caroline of Monaco interviewed me once and asked me how. She said was it 'just like that?' and I said 'Yes, just like that!'"

"Well," interrupted an eavesdropping guest. "Maybe it's because of his own lovely children."

Nine to be exact. And four wives, the latest being Princess Madjah, 20. Last night, they all boarded the 727 and headed for Los Angeles to whale-watch off Catalina.

Although Talal bought Arthur Godfrey's 2,200-acre Northern Virginia estate in 1979, Washington is not the sort of town where princes usually roam. Last night, everyone stared unabashedly at the prince and his long flowing robe. Flashbulbs popped. People elbowed their way in to get close.

Talal was a genuine crowd-pleaser and seemed to live up to princely expectations. At one point he took a tray of kiwi from a waiter and passed it around himself. The women were charmed. And then he instructed a photographer to make sure everyone who wanted a picture with him got one promptly in the mail.

Najeeb Halaby, a Washingtonian and father of Queen Noor of Jordan, was among several hundred guests circulating through the Sculpture Garden.

"Well, the queen is hours or days away from her third child," Halaby said. "That's the big royal news. We're hoping for a girl, as the saying goes. I'm going over there as soon as it's appropriate for a grandfather to do so. Grandfathers are never needed at birth, you know . . ."

Other guests included Senate Foreign Relations Committee Chairman Charles H. Percy (R-Ill.), Robert S. McNamara, who is currently serving on the president's panel for the MX missile, Saudi Ambassador Faisal Alhegelan, Moroccan Ambassador Ali Bengelloun and public relations executive Joan Braden.

Last night's party was given by Smithsonian Secretary S. Dillon Ripley and was double-billed as a party for the prince as well as a premiere of "Mirror of Kings." The 15-minute film was based on an illustrated Middle East book of animal fables, which over the years served to teach morals.

"The film? Oh, it was adorable," said one guest, popping a tiny spinach pie into her mouth. "But have you seen the stuffed grape leaves?"