Moscow ? Time is running out on the single – and certainly swinging – days of the man known as Russia’s most eligible bachelor. Mikhail Prokhorov, the tall, feverish spender who amassed a worth of $13.5 billion running the world’s largest nickel producer, is getting hitched May 3.

To win a bet. Or so the story goes.

Perhaps that’s the only way to get him to settle down. Prokhorov, 41, after all, is known for throwing decadent bashes where the women are aplenty and the cognac alone costs more than most Russians make in years. The excess has gotten him in trouble of late: Prokhorov was arrested in a glamorous resort town in the French Alps shortly after New Year’s, in connection with a prostitution investigation. Authorities released him, without pressing charges, after four days.

It is unclear, at least to the inquiring public, whom Prokhorov might be marrying and whether love is in any way involved.

Kseniya Sobchak, an impeccably appointed blond socialite who hosts a television reality show called “Dom-2” and is referred to as Russia’s Paris Hilton, has been mentioned as a contender. She already owns a wedding dress, she has pointed out; she was engaged to a Russian businessman trained at Harvard University and had planned a high-society wedding in 2005 that was called off.

A fair question: How did it come to this? Prokhorov apparently made a bet – with whom, and for what, is not known – to wed before he turns 42, which happens on the third of May.

And, it seems, he is a man of his word. Or he hates to lose. Or, perhaps, both.

He reportedly has said, enigmatically, that he will wed the “pervoi vstrechnoi,” which means, literally, the “first one he meets.”

“Mishka said he would marry the first girl who came along,” the newspaper Tvoi Dyen recently quoted a businessman “closely connected to the oligarch” as saying. “But he will have to choose her no later than March because it’s necessary to draw up all the documents before the marriage.”

There might be some other documents to draw up as well: those required for divorce. The same person from the Moscow registry office who will perform the marriage ceremony is expected to dissolve it, too, after five days.