This number is the result of a "large number duel"[1] between MIT Associate Professor Agustin Rayo (The Mexican Multiplier) and Princeton Associate Professor Adam N. Elga (Dr. Evil)[2]. Possible the world record largest number by some standards.

[1] https://www.scottaaronson.com/writings/bignumbers.html

[2] http://tech.mit.edu/V126/N64/64largenumber.html