Skewes' number

noun1

1. •
   Any of several extremely large numbers used as upper bounds for the smallest natural number x for which π(x)> operatorname li(x), where π is the prime-counting function and li is the logarithmic integral function. These bounds have since been improved by others.

   • With this extension, the number system exceeds a number of previously-named giants, such as Archimedes' largest number, Kasner's googolplex, Skewes' number and Candelaria's googoltriplex. — 1976