Do[
 tmp = EulerPhi[i];
 If[i - 1 == tmp,
  Print["\[CurlyPhi](", i, ")=", tmp, ", is prime"]
  ,
  Print["\[CurlyPhi](", i, ")=", tmp]
  ]
 ,
 {i, 25}
 ]
Count[EulerPhi[Range[100]] - Range[100], -1]
Count[EulerPhi[Range[1000]] - Range[1000], -1]
Count[EulerPhi[Range[10000]] - Range[10000], -1]
Count[EulerPhi[Range[100000]] - Range[100000], -1]
(*Alternative much faster way of findings the number primes up to a number*)
(*PrimePi[100]*)
(*PrimePi[1000]*)
(*PrimePi[10000]*)
(*PrimePi[100000]*)