Project Euler Problem 3

Largest prime factor

The prime factors of 13195 are 5, 7, 13 and 29.
What is the largest prime factor of the number 600851475143 ?

public class Program

        public static void Main(string[] args)

            Console.WriteLine(Problem3.LargestPrimeFactor(600851475143));

class Problem3

        internal static long LargestPrimeFactor(long number)

            long i = 2, factor=1;

            while(true)

                if (number % i == 0)

                    factor = number / i;

                    if (IsPrimeNumber(factor))

                        return factor;

                i++;

        private static bool IsPrimeNumber(long number)

            long divisor = 2;

            for (long i = number / 2; i > 1; i+=0)

                if (number % i == 0) return false;

                i = number / (++divisor);

            return true;

}