Check whether factorial of N is divisible by sum of first N natural numbers | Function to check whether a number is prime or not . ; Count variable to store the number of factors of ' num ' ; Counting the number of factors ; If number is prime return true ; Function to check for divisibility ; if ' n ' equals 1 then divisibility is possible ; Else check whether ' n + 1' is prime or not ; If ' n + 1' is prime then ' n ! ' is not divisible by ' n * ( n + 1 ) / 2' ; else divisibility occurs ; Driver Code ; Test for n = 3 ; Test for n = 4
class GfG { static boolean is_prime ( int num ) { int count = 0 ; for ( int i = 1 ; i * i <= ( num ) ; i ++ ) { if ( ( num ) % i == 0 ) { if ( i * i != ( num ) ) count += 2 ; else count ++ ; } } if ( count == 2 ) return true ; else return false ; } static String is_divisible ( int n ) { if ( n == 1 ) { return " YES " ; } else { if ( is_prime ( n + 1 ) ) return " NO " ; else return " YES " ; } } public static void main ( String [ ] args ) { int n ; n = 3 ; System . out . println ( is_divisible ( n ) ) ; n = 4 ; System . out . println ( is_divisible ( n ) ) ; } }