if (n-1) is divisible by φ(n) then there is no prime p such that p^2|m.
Thanks...
I suppose you meant to say.
Let's proceed by contradiction, suppose on the contrary that there were a primesuch that
. Clearly
since
and
are coprime, however
implies
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, and since
we have that
which is a contradiction.
Check this by using the formula
, where the products runs over all primes dividing
.