Break a number such that sum of maximum divisors of all parts is minimum | Function to check if a number is prime or not . ; If n is an even number ( we can write it as sum of two primes ) ; If n is odd and n - 2 is prime . ; If n is odd , n - 3 must be even . ; Driver code
< ? php function isPrime ( $ n ) { $ i = 2 ; while ( $ i * $ i <= $ n ) { if ( $ n % $ i == 0 ) return false ; $ i ++ ; } return true ; } function minimumSum ( $ n ) { if ( isPrime ( $ n ) ) return 1 ; if ( $ n % 2 == 0 ) return 2 ; if ( isPrime ( $ n - 2 ) ) return 2 ; return 3 ; } $ n = 27 ; echo minimumSum ( $ n ) ; ? >