126

This number is a composite.

126*126!₈ + 1 is prime. [Fougeron]

The smallest multidigit number such that the sum of its distinct prime factors equals the product of its digits. [Russo]

126 multiplied by the 126th Lucas number plus and minus one results in twin primes of prime length (29 digits). This is the largest such Lucas number less than 10^2000. [Opao]

126^126 + 126! + 126*126 + 126/126 + 126 is prime. It is interesting that the digits of 126 have the same property. [Firoozbakht]

The prime gap that covers the first century with no primes (from 1671800 to 1671899) has length 126 (from 1671781 to 1671907).

126! - 126*126 - 126/126 is a 212-digit prime. [Firoozbakht]