# 89

This number is a prime.

Single Curio View: (Seek other curios for this number)

Hugo Steinhaus (1887-1972) proved that if you take any positive integer, find the sum of the squares of its digits, and then repeat; that you will either come to 1 or the cyclic sequence 145, 42, 20, 4, 16, 37, 58, **89**.

Submitted: 2003-01-27 01:01:25; Last Modified: 2009-01-17 15:55:33.

Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell