Source: wikibot/self-number
= Self number
{wiki=Self_number}
A self number (also known as a Belgian number or a non-generable number) is an integer that cannot be expressed as the sum of a positive integer and the sum of its digits. In other words, a number \\( n \\) is a self number if there is no positive integer \\( m \\) such that: \\\[ n = m + S(m) \\\] where \\( S(m) \\) represents the sum of the digits of \\( m \\).