What is a googolplex?
In mathematics, a googol is 10100 (10 to the power of 100), or the number 1 followed by 100 zeros.
A googolplex is 10googol, or the number 1 followed by a googol of zeros.
A googol and a googolplex are both so large that if one was able to count at lightspeed (i.e. in one second, you can count from 1 to 186,000), it would still take you approximately 1015 years to count to googol and 1018 years to count to googolplex. Both amounts of time are longer than the universe is estimated to have been around.
A number larger still than a googolplex is the Graham's number, which is so large that not even power towers can be used to write it out (while a googolplex can also be written as 1010100, Graham's number can't be written with exponents).
Graham's number is so large that if you add all the atoms in the universe together, you would still not get to it. But there is a way to calculate Graham's Number.
5 Up arrows^3 equal G1 but that's not Graham's Number 6 uparrows^3 equal G2 so 69 up arrows^3 equal Grahams number