2007/5/11, Anthony wikilegal@inbox.org:
Huh. I got something on a much lower order. (This is probably due to something exceptionally stupid like having done the calculation assuming digits were bits, and juggling numbers mentally... some days, I am amazed I ever passed my exams)
I'm not convinced that my numbers are exact, but I have heard 128 bits referred to several times as being more than the number of atoms in the universe.
128 bits gives 2^128 possibilities, which is in the order of magnitude of 10^38. Which is well less than the number of atoms in the universe (which, IIRC is somewhere in the 10^70 range), but fits quite well with the number you gave.