Find Primes

using System;

class FindPrimes
{
    static void Main()
    {
        int countPrimes = 1;
        int number = 3;

        while (countPrimes < 251)
        {
            bool isPrime = true;

            for (int divisor = 2; divisor <= Math.Sqrt(number); divisor++)
            {
                if (number % divisor == 0)
                {
                    isPrime = false;
                    break;
                }
            }

            if (isPrime)
            {
                countPrimes++;

                if (countPrimes == 24 || countPrimes == 101 || countPrimes == 251)
                {
                    Console.WriteLine(
                        "The {0}{1} prime number is: {2}",
                        countPrimes, countPrimes == 24 ? "th" : "st", number);
                }
            }

            number++;
        }
    }
}