c++ int i aşma sorunu?

const long numm = 600851475143; 
              long largestFact = 0; 
              long[] factors = new long[2]; 
   
              for (long i = 2; i * i < numm; i++) 
              { 
                  if (numm % i == 0) 
                  { // It is a divisor 
                      factors[0] = i; 
                      factors[1] = numm / i; 
   
                      for (int k = 0; k < 2; k++) 
                      { 
                          bool isPrime = true; 
                          for (long j = 2; j * j < factors[k]; j++) 
                          { 
                              if (factors[k] % j == 0) 
                              { 
                                  isPrime = false; 
                                  break; 
                              } 
                          } 
                          if (isPrime && factors[k] > largestFact) 
                          { 
                              largestFact = factors[k]; 
                          } 
                      } 
                  } 
              } Console.ReadKey();