Calculate Sum of Digits in Python

Enter number: 57
Sum: 12

def main():
    """
    Prints the sum of the digits of a number.
    """

    RADIX = 10

    num = abs(int(input("Enter number: ")))
    sum = 0
    while num != 0:
        digit = num % RADIX
        sum += digit
        num //= RADIX

    print(sum)


if __name__ == "__main__":
    main()