Isaac Asimov has written quite a bit on large numbers. He writes about T-numbers in "Adding a dimension". Where T-1 is a trilion, and T-2 is a trilion trilion. For instance, T-2 nucleons are a few grams of mass, and T-5 nucleons are a thousand solar systems. Big numbers indeed.

In Skewered he describes a different large-number system (http://www.scribd.com/doc/275741/Isaac-Asimov-Skewered).

Asimov's facination with big numbers lasted a lifetime.