Convert number into text in asp.net

Function of convert number into text


public static string NumberToText(int n)
    {
        if (n < 0)
            return "Minus " + NumberToText(-n);
        else if (n == 0)
            return "";
        else if (n <= 19)
            return new string[] {"ONE", "TWO", "THREE", "FOUR", "FIVE", "SIX", "SEVEN", "EIGHT",
         "NINE", "TEN", "ELEVEN", "TWELVE", "THIRTEEN", "FOURTEEN", "FIFTEEN", "SIXTEEN",
         "SEVENTEEN", "EIGHTEEN", "NINETEEN"}[n - 1] + " ";
        else if (n <= 99)
            return new string[] {"TWENTY", "THIRTY", "FORTY", "FIFTY", "SIXTY", "SEVENTY",
         "EIGHTY", "NINETY"}[n / 10 - 2] + " " + NumberToText(n % 10);
        else if (n <= 199)
            return "ONE HUNDRED " + NumberToText(n % 100);
        else if (n <= 999)
            return NumberToText(n / 100) + "HUNDRED " + NumberToText(n % 100);
        else if (n <= 1999)
            return "ONE THOUSAND " + NumberToText(n % 1000);
        else if (n <= 99999)
            return NumberToText(n / 1000) + "THOUSAND " + NumberToText(n % 1000);

        else if (n <= 199999)
            return "ONE LAC " + NumberToText(n % 100000);
        else if (n <= 9999999)
            return NumberToText(n / 100000) + "LAC " + NumberToText(n % 100000);
        else if (n <= 19999999)
            return "ONE CRORE" + NumberToText(n % 10000000);
        else if (n <= 999999999)
            return NumberToText(n / 10000000) + "CRORE " + NumberToText(n % 10000000);
        else if (n <= 1999999999)
            return "ONE BILLION " + NumberToText(n % 1000000000);
        else
            return NumberToText(n / 1000000000) + "BILLION " + NumberToText(n % 1000000000);
    }