Something

    public static DevInt root(DevInt number, DevInt root) {
        if (number == 0) return 0;
        Console.WriteLine("number = " + number + "\nroot = " + root);
        DevInt low = DevInt.root(DevInt.rightShift(number,root), root) << 1; 
        DevInt high = low + 1;
        Console.WriteLine("low = " + low + "\nhigh = " + high);
        return DevInt.pow(high, root) > number ? low : high; 
    }