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- For which Natural $n\ge2: \phi(n)=n/2$ 4 answers
For $n\ge1$, let $\phi(n)$ be the number of positive integers $\le n$, which are relatively prime to $n$
i. Find all $n$ such that $\phi(n)=\frac n2$ ii. Find all $n$ such that $\phi(n)=4$.
I know the formula for suker totient function but that is not telling me anything. Please help.