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"""

== Perfect Number ==

In number theory, a perfect number is a positive integer that is equal to the sum of

its positive divisors, excluding the number itself.

For example: 6 ==> divisors[1, 2, 3, 6]

Excluding 6, the sum(divisors) is 1 + 2 + 3 = 6

So, 6 is a Perfect Number

Other examples of Perfect Numbers: 28, 486, ...

https://en.wikipedia.org/wiki/Perfect_number

"""

def perfect(number: int) -> bool:

"""

>>> perfect(27)

False

>>> perfect(28)

True

>>> perfect(29)

False

Start from 1 because dividing by 0 will raise ZeroDivisionError.

A number at most can be divisible by the half of the number except the number

itself. For example, 6 is at most can be divisible by 3 except by 6 itself.

"""

return sum(i for i in range(1, number // 2 + 1) if number % i == 0) == number

if __name__ == "__main__":

print("Program to check whether a number is a Perfect number or not...")

number = int(input("Enter number: ").strip())

print(f"{number} is {'' if perfect(number) else 'not '}a Perfect Number.")

Sunbelt Computer Software