How many zeros are in a kajillion?

Answer 1

37.5 zeros.

Since it is a made up name for a number, it can have as many zeros as you like.

Answer 2

Kajillion sounds to be a ficitional number, but mejillion and gijillion aren't. I think you're meaning "kalillion", which is 10^(3*(10^(3*10^3000))+3). Note that all numbers ending in "jillion" or "zillion" are indefinite and have fictional quantities.