text: now we have to iterate only for integers who does not have prime factor 2 and 3
code: for ( int i = 5 ; i <= sqrt ( n ) ; i += 6 ) { while ( n % i == 0 ) { maxPrime = i ; n = n / i ; } while ( n % ( i + 2 ) == 0 ) { maxPrime = i + 2 ; n = n / ( i + 2 ) ; } }