NumberToWords in c#

public static string NumberToWords(int number)
{
if (number == 0)
return "zero";

if (number < 0) return "minus " + NumberToWords(Math.Abs(number)); string words = ""; if ((number / 1000000) > 0)
{
words += NumberToWords(number / 1000000) + " million ";
number %= 1000000;
}

if ((number / 1000) > 0)
{
words += NumberToWords(number / 1000) + " thousand ";
number %= 1000;
}

if ((number / 100) > 0)
{
words += NumberToWords(number / 100) + " hundred ";
number %= 100;
}

if (number > 0)
{
if (words != "")
words += "and ";

var unitsMap = new[] { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeen", "eighteen", "nineteen" };
var tensMap = new[] { "zero", "ten", "twenty", "thirty", "forty", "fifty", "sixty", "seventy", "eighty", "ninety" };

if (number < 20) words += unitsMap[number]; else { words += tensMap[number / 10]; if ((number % 10) > 0)
words += "-" + unitsMap[number % 10];
}
}

return words;
}