Project Euler Problem 4

Largest palindrome product

A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.
Find the largest palindrome made from the product of two 3-digit numbers.

public class Program

{

    public static void Main(string[] args)

    {

        Console.WriteLine(Problem4.LargestPalindromeProduct(3));

    }

}

class Problem4

{

    internal static double LargestPalindromeProduct(int digits)

    {

        double upperLimit = Math.Pow(10, digits) - 1;

        double lowerLimit = Math.Pow(10, digits - 1) - 1;

        double palindrome = 0;

        for (double number = upperLimit; number > lowerLimit; number--)

        {

            palindrome = double.Parse(MakePalindrome(number.ToString()));

            for (double divisor = upperLimit; divisor > lowerLimit; divisor--)

            {

                if (palindrome > divisor * divisor)

                {

                    break;

                }

                if (palindrome % divisor == 0 && (palindrome / divisor) < upperLimit)

                {

                    return palindrome;

                }

            }

        }

        return palindrome;

    }

    private static string MakePalindrome(string number)

    {

        return number + new string(number.Reverse().ToArray());

    }

}