Unprimeable Numbers | function to check if N is prime ; Corner cases ; This is checked so that we can skip middle five numbers in below loop ; function to check if n is a unprimeable Number ; number should be composite ; converting N to string ; loop to change digit at every character one by one . ; loop to store every digit one by one at index j ; Driver Code ; Function Call
function isPrime ( n ) { if ( n <= 1 ) return false ; if ( n <= 3 ) return true ; if ( n % 2 == 0 n % 3 == 0 ) return false ; for ( var i = 5 ; i * i <= n ; i = i + 6 ) if ( n % i == 0 || n % ( i + 2 ) == 0 ) return false ; return true ; } function isUnPrimeableNum ( N ) { if ( isPrime ( N ) ) return false ; var s = N . toString ( ) ; for ( var j = 0 ; j < s . length ; j ++ ) { var str = s ; for ( var i = 0 ; i <= 9 ; i ++ ) { var c = ' ' + parseInt ( i ) ; str [ j ] = c ; var Num = parseInt ( str ) ; if ( str [ j ] != s [ j ] && isPrime ( Num ) ) { return false ; } } } return true ; } var N = 200 ; if ( isUnPrimeableNum ( N ) ) document . write ( " " ) ; else document . write ( " " ) ;