Check if the given number is a prime number

        public static bool DoIsPrimeNumber(int n)
        {
            // fetch the factors for n
            List<int> factors = DoGetFactors(n);

            return factors.Count > 2 ? false : true;
        }
        

How it works:

For a given number n, we’ll find out all the factors and then see if the Count of the factors is more than 2 or not. If it is two we’ll return it is a prime, since by definition a prime number can’t have more than 2 factors.