222361domain: NPropertiesPrimalityPrimeyesAppears in sequencesa(n) = largest prime factor of n^n - 1.at n=18A006486Greatest prime factor of n^10+1.at n=19A240553Smallest beastly prime in base n: smallest prime p with a base-n expansion containing the substring 666.at n=26A286342Prime numbersat n=19809