Smith number

http://en.wikipedia.org/wiki/Smith_number

A Smith number is a composite number for which, in a given base (in base 10 by default), the sum of its digits is equal to the sum of the digits in its prime factorization.

For example,

378 = 2 * 3 * 3 * 3 * 7 is a Smith number since 3 + 7 + 8 = 2 + 3 + 3 + 3 + 7.

Smith numbers were named by Albert Wilansky of Lehigh University. He noticed the property in the phone number (493-7775) of his brother-in-law Harold Smith:

4937775 = 3 * 5 * 5 * 65837, while

4 + 9 + 3 + 7 + 7 + 7 + 5 = 3 + 5 + 5 + 6 + 5 + 8 + 3 + 7 = 42.

Is your phone number a Smith number?


Fascinating Smith Numbers

http://www.shyamsundergupta.com/smith.htm