Which of the following statement(s) is/are true?
1
For any integer n > 2, Euler's function ϕ(n) is even
2
For any integer n > 2, Euler's function ϕ(n) is odd
3
For any integer n > 2, Euler's function ϕ(n) is rational number
4
For any integer n > 2, Euler's function ϕ(n) is zero