The Skewes Number, written , is the largest number where is true, assuming the Riemann hypothesis is true. Here, is the prime counting function and is the logarithmic integral.[1]
The original upper bound for the number was , in the vicinity of the googolduplex.
The second Skewes Number, , is the largest number where is true, assuming the Riemann hypothesis is false. It is larger than the original Skewes Number, .