// As for a googolplex - if I remember correctly, there isn't enough room in the known universe to write the number out in its full form ... //
Yup, you do remember correctly. Depending, perhaps, on what assumptions you make about the universe at small scales, this is probably true for any number on the order of a googol squared, though, which is much, much smaller than a googol!
What's perhaps even more impressive is that, if you assume that you could fit each digit into the tiniest possible space, and in the tiniest possible fraction of a second, scrubbed every digit out and instantly replaced them with the next lot... you still wouldn't get close until the Universe was about a billion billion billion.... billion times older, where there are about a (billion billion billion)^4 iterations of the word "billion" :P
I can't be bothered to check how precise this is but it's pretty close.