How many digits are in Graham's Number?

G = g₆₄     Where g₁ = 3↑↑↑↑3  and g_n = 3↑^g_n-1 3

Here I've used knuth's up-arrow notation, whice is used to indicate different levels of hyperoperations. 

Graham's number is so gigantic that even it's number of digits is more than a googleplex. Much, MUCH more indeed. 

21,21,21,21,21,21,21,21,21

I don't know.....(and maybe nobody else does, either.....???).....whatever this number is, it makes the "googleplex" (another extremely large number) look like child's play...!!!

It is a number generated through "towers of powers".....and it was the focus of a recent article here........http://waitbutwhy.com/2014/11/1000000-grahams-number.html

Warning....this is pretty heavy duty...!!!....I got about halfway through the "Graham's Number" stuff before I had to cry, "Uncle!!!"

I may go back and look at it someday....but.....it won't be today.....!!!

Good luck.......