Factorion

A **factorion** is a special type of number in mathematics that is equal to the sum of the factorials of its digits. In other words, a number \( n \) is a factorion if: \[ n = d_1! + d_2! + d_3! + \ldots + d_k! \] where \( d_1, d_2, \ldots, d_k \) are the digits of \( n \), and \( !