222

This number is a composite.

The number 222² + 222²² + 222²²² + 1 is prime. [Patterson]

222 is the smallest repdigit such that the product of itself and all truncations of itself plus and minus one results in twin primes. I.e., 222*22*2 ± 1 are twin primes. [Opao]

The 222nd Fibonacci number + 222-1 is a prime number. [Raghava]

222 is the sum of all 2-digit primes formed from consecutive digits. [Silva]

109 and 113 are the smallest pair of consecutive primes with a repdigit sum (222). The next such pair are 4441 and 4447. [Gaydos]

The sum of two emirp pairs plus 2 is a repunit, i.e., 37 + 37 + 2 + 73 +73 = 222. [Wiszowaty]