A Googol is 10 to the power of 100
or 1 with 100 zero's: like this:
10,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000
A googol is greater than the number of atoms in the observable universe, which has been variously estimated from 1079 up to 1081
As for a googolplex: A the number one followed by one googol zeroes, or ten raised to the power of one googol: