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 \( m \).