public static bool IsReversableNumber(this Int64 source) { if (source.ToString().EndsWith("0") || source.AllDigitsAreEven()) { return(false); } var reversedSource = Int64.Parse(new string(source.ToString().Reverse().ToArray())); var isReversableNumber = (source + reversedSource).AllDigitsAreOdd(); return(isReversableNumber); }