code: public class NumberToWordsConverter { // works upto 9999999
  
  	final private  static String[] units = {"Zero","One","Two","Three","Four",
  		"Five","Six","Seven","Eight","Nine","Ten",
  		"Eleven","Twelve","Thirteen","Fourteen","Fifteen",
  		"Sixteen","Seventeen","Eighteen","Nineteen"};
  	final private static String[] tens = {"","","Twenty","Thirty","Forty","Fifty",
  		"Sixty","Seventy","Eighty","Ninety"};
  
  	public static String convert(Integer i) {
  		//
  		if( i < 20)  return units[i];
  		if( i < 100) return tens[i/10] + ((i % 10 > 0)? " " + convert(i % 10):"");
  		if( i < 1000) return units[i/100] + " Hundred" + ((i % 100 > 0)?" and " + convert(i % 100):"");
  		if( i < 1000000) return convert(i / 1000) + " Thousand " + ((i % 1000 > 0)? " " + convert(i % 1000):"") ;
  		return convert(i / 1000000) + " Million " + ((i % 1000000 > 0)? " " + convert(i % 1000000):"") ;
  	}
  }
  