problem3

var a = 600851475143;
var isPrime = function (j) { 
  for ( j = (i-1); j > 1 ; j--) {
    if (i % j === 0) {
      return false;
    } else {
      return true;
    }
  }
};

//solving for numbers smaller than 10000000

for (var i = 1; i < 100000000; i++) {
 if (a % i === 0) {
     if (isPrime(i)) {
       var answer = i;
     }
  }
}  

console.log(answer);