Check if Euler Totient Function is same for a given number and twice of that number | Java program of the above approach ; Function to find the Euler 's Totient Function ; Initialize result as N ; Consider all prime factors of n and subtract their multiples from result ; Return the count ; Function to check if phi ( n ) is equals phi ( 2 * n ) ; Driver Code
import java . util . * ; class GFG { static int phi ( int n ) { int result = 1 ; for ( int p = 2 ; p < n ; p ++ ) { if ( __gcd ( p , n ) == 1 ) { result ++ ; } } return result ; } static boolean sameEulerTotient ( int n ) { return phi ( n ) == phi ( 2 * n ) ; } static int __gcd ( int a , int b ) { return b == 0 ? a : __gcd ( b , a % b ) ; } public static void main ( String [ ] args ) { int N = 13 ; if ( sameEulerTotient ( N ) ) System . out . print ( " Yes " ) ; else System . out . print ( " No " ) ; } }