Advanced Topics 2. Prime Checker

// Write a Boolean method IsPrime(n) that check whether a given integer number n is prime.

namespace _02.PrimeChecker
{
    using System;

    public class PrimeChecker
    {
        public static void Main(string[] args)
        {
            checked
            {
                Console.Write("Enter a Integer number: ");
                long num = long.Parse(Console.ReadLine());

                num = Math.Abs(num);
                bool isPrimeNum = CheckTheIntegerNumberIsPrimeOrNot(num);
                Console.WriteLine("That number Is Prime: {0} !", isPrimeNum);
            }
        }

        private static bool CheckTheIntegerNumberIsPrimeOrNot(long num)
        {
            checked
            {
                if (num < 2)
                {
                    return false;
                }
                else
                {
                    bool isPrime = true;
                    long maxDivider = (long)Math.Sqrt(num);
                    for (long i = 2; i <= maxDivider; i++)
                    {
                        if (num % i == 0)
                        {
                            isPrime = false;
                            break;
                        }
                    }

                    return isPrime;
                }
            }
        }
    }
}