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- Find all n such that $\phi(n) = n/2$ 3 answers
I just came across this problem while studying the Euler-Totient function :
Find all integers such that $\phi(n)$ = $n$/2.
Now, I know that $\phi(n)$ gives the count of the total number of positive integers upto $n$ that are relatively prime to $n$. But I have no clue how to go about solving this question.