Calling someone a “blank” professor [closed]

You're probably thinking of "The Absent-Minded Professor," a term popularized by a Disney film from 1961. It's a stock character at this point with roots in mythology (Wikipedia):

The phrase "absent-minded professor" is also commonly used more generally in English to describe people who are so engrossed in their "own world" that they fail to keep track of their surroundings. It is a common stereotype that professors get so obsessed with their research that they pay little attention to anything else.

"The Nutty Professor" is more of a Jekyll and Hyde character, though that is a common a reference as well, also from a film in the 60s that was remade in the 90s. Not as good a fit for your description, but the two get confused.