This sounds like The Sleeping God, a story by Jesco von Puttkamer. It was published in Sondra Marshak and Myrna Culbreath's Star Trek: The New Voyages 2, in 1978. (Yes, it's a Star Trek short story.)
The story starts with Nagha, an artificial intelligence:
The Nagha was a child.
She was all but omniscient and omnipotent, of immense size and
gigantic capabilities. But she was only a child - a big humorless
...race of intelligent beings that constructed the original miniature
cell of the Nagha...the computer complex that would one day, many
millions of years later, think of conquering another Universe.
The Enterprise is on its way to investigate the mysterious attacks, when it receives orders to divert to Raga's Planet to pick up 'the Sleeper'.
"There is not much available on him, Captain. He is definitely human,
apparently of Indian descent and is maintained in suspended
animation....It seems that about one hundred years ago a small boy was
discovered as a stowaway on a ship bound for Raga's Planet. He gave
his name simply as Singa..."
"One day, now fully matured, he demanded to see the Council of Elders
and the local representatives of the Federation. That was some
eighty-five years ago. His story seemed somewhat incredible. He
claimed to be a mutant, having been born to his parents from mutated
genes which had been traumatized by radiation leaks in a
malfunctioning space-ship drive they were working on. The mutation had
endowed him with superior capabilities, and he was offering himself to
the Elders for service to mankind."
"...A special investigatory team of scientists was dispatched to
Raga's Planet. They found Singa's mental powers to be far greater than
they had first assumed from his original statements. They were truly
immense. Captain, there is at present no being in the known Universe
that could match the mental capabilities of the Sleeper."
"...Singa may have been a mental mutant, but he aged normally, just
like any other human being. Far-sighted people warned that a truly
unique, never-again-repeatable opportunity would go to waste if
nothing was done. And so..." Kirk nodded. "So they put him in