Sometimes the callers will telephone from Zurich late at night, but whatever the hour and whoever the caller, Michael Blumenthal is always glad to hear the phone ring. We are speaking here of Michael Blumenthal, the 31-year-old Washington poet, not Michael Blumenthal, the secretary of the treasury who left his government job a year ago.

But many callers don't know that the only Michael Blumenthal listed in the Washington phone book is not the former federal money man.

So poet Blumenthal has received, in addition to calls from Swiss bankers, a couple of top corporate job offers and an invitation to speak at the Kennedy School of Government commencement ceremony.

"It would have probably been my only chance to read poetry at Harvard," says Blumenthal, who recently won the 1980 Poets of North America First Book Award for his collection, Sympathetic Magic.

But Blumenthal isn't complaining. Restaurants always seem to have room for him on their reservation lists, some people have attended his poetry readings thinking he was the other Blumenthal, and former Sen. Wendall Anderson once broke up his schedule to see Blumenthal. The wrong Blumenthal.

Most delighted is Blumenthal's father, a German immigrant. When Jimmy Carter appointed the other Blumenthal treasury secretary, telegrams of congratulations poured in from old friends in Europe delighted that their friends's son had done so well for himself at so young an age.