 Multiplicative group of integers modulo n

The multiplicative group of integers modulo $n$ consists of the residue classes coprime to $n$. It has order $\phi (n)$.

The multiplicative group of integers modulo \( n \), often denoted as \( (\mathbb{Z}/n\mathbb{Z})^* \) or \( U(n) \), is the set of integers that are relatively prime to \( n \) under the operation of multiplication, with the multiplication performed modulo \( n \).