# 155

This number is a composite.

2^{2} + 3! + 5! + 7^{2} - 11 - 13 = 155. [Russ]

155 is the only three-digit number such that 155^155-155+1 is prime. [Opao]

The sum of primes between smallest and largest prime factor of itself. [Post]

155 = prime(1+5+5) * π(1+5+5). It is the smallest number of this form. [Bajpai]

155 and 156 are the smallest pair of consecutive integers whose highest prime factors (31 and 13) are anagrams of each other. [Gaydos]

Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell