Euler 's Totient Function | Java program to calculate Euler ' s ▁ Totient ▁ Function ▁ using ▁ Euler ' s product formula ; Initialize result as n ; Consider all prime factors of n and for every prime factor p , multiply result with ( 1 - 1 / p ) ; Check if p is a prime factor . ; If yes , then update n and result ; If n has a prime factor greater than sqrt ( n ) ( There can be at - most one such prime factor ) ; Driver program to test above function
import java . io . * ; class GFG { static int phi ( int n ) { float result = n ; for ( int p = 2 ; p * p <= n ; ++ p ) { if ( n % p == 0 ) { while ( n % p == 0 ) n /= p ; result *= ( 1.0 - ( 1.0 / ( float ) p ) ) ; } } if ( n > 1 ) result *= ( 1.0 - ( 1.0 / ( float ) n ) ) ; return ( int ) result ; } public static void main ( String args [ ] ) { int n ; for ( n = 1 ; n <= 10 ; n ++ ) System . out . println ( " phi ( " + n + " ) ▁ = ▁ " + phi ( n ) ) ; } }