SOLVED. sci fi from around the 50's [s]

[Dane]

A Scientist was to be killed put into suspended animation so his girl friend could rescue him didn't work out is found centuries later. The entire time he had been conscious exploring math and memories so he didn't go insane, Aliens need him to save the universe.

[Slinkyboy]

This sounds a lot like Clifford Simak's Cosmic Engineers.

Person conscious for ages while in suspended animation working out math problems to stay sane... working with aliens to somehow save the universe...

...but the math genius in Simak's book is a woman.

[Dane]

yep my memory was wrong . that's it thanks.