Graham's Number is just the pretentious cousin of infinity.

>yes, it technically has a limit, but if every molecule in the observable universe represented a 0 in a number to quantify it, every molecule in the universe wouldn't equal 0.000000001% of the total of Graham's Number

Basically, it's infinity. You can't even describe HOW to write down a number so big, so for all intents and purposes, there is no upper limit.