Euler Phi-Function is a Multiplicative Function

Let \(n\) be a positive integer. Recall that the Euler phi-function \(\phi(n)\) is defined as the number of positive integers less than or equal to \(n\) and relatively prime to \(n.\) Note that \(\phi(1)=1.\) We have seen that Euler used this function to generalize the Fermat's Little Theorem. It is sometimes needed to calculate the value \(\phi(n)\) of… Read More »