Skewes's number

In number theory, Skewes's number is any of several large numbers used by the South African mathematician Stanley Skewes as upper bounds for the smallest natural number ${\displaystyle x}$ for which

${\displaystyle \pi (x)>\operatorname {li} (x),}$

where π is the prime-counting function and li is the logarithmic integral function. Skewes's number is much larger, but it is now known that there is a crossing between ${\displaystyle \pi (x)<\operatorname {li} (x)}$ and ${\displaystyle \pi (x)>\operatorname {li} (x)}$ near ${\displaystyle e^{727.95133}<1.397\times 10^{316}.}$ It is not known whether it is the smallest crossing.