Source: wikibot/pillai-prime
= Pillai prime
{wiki=Pillai_prime}
A Pillai prime is a type of prime number characterized by its relationship to the factorial function. Specifically, a Pillai prime \\( p \\) is defined as a prime number for which there exists a positive integer \\( n \\) such that \\( n! \\equiv -1 \\mod p \\). This means that when \\( n! \\) (the factorial of \\( n \\)) is divided by the prime \\( p \\), it leaves a remainder of \\( p - 1 \\).