This number is a composite.
818 is the smallest palindrome that may be expressed as the sum of the squares of two primes (232 + 172). [King]
818 is the only 3-digit tetradic integer such that the sum of the differences of the number and each digit raised to the digit is prime. I.e., (818-8)^8+(818-1)^1+(818-8)^8 is prime. [Opao]
Printed from the PrimePages <primes.utm.edu> © G. L. Honaker and Chris K. Caldwell