is_factorial.py

def factorial(number: int):
    if number == 0:
        r = 1
    else:
        r = number * factorial(number - 1)
    return r


def is_factorial(number: int) -> bool:
    result = False
    operand_number = number
    while operand_number >= 1:
        fact_result = factorial(operand_number)
        if number == fact_result:
            result = True
            break
        else:
            operand_number = operand_number - 1
    return result


print(is_factorial(3))  # False
print(is_factorial(6))  # True
print(is_factorial(0))  # False
print(is_factorial(1))  # True
print(is_factorial(24))  # True
print(is_factorial(120))  # True
print(is_factorial(125))  # False
print(is_factorial(720))  # True
print(is_factorial(-6))  # False