Nontotient

A **nontotient** is a positive integer \( n \) for which there is no integer \( k \) such that \( k \) and \( n \) are coprime, and \( \phi(k) = n \), where \( \phi \) is the Euler's totient function. The Euler's totient function \( \phi(k) \) counts the number of integers up to \( k \) that are coprime to \( k \).