Python Program to Check a Perfect Number

This article is created to cover the program in Python that checks whether a number entered by the user is a perfect number or not. Here is a list of programs covered in this article:

• Check the perfect number using the for loop.
• Check the perfect number using the while loop.

What is a perfect number?

A perfect number is a number that is equal to the sum of its positive divisors, excluding the number itself. That is, the number 6 has divisors 1, 2, and 3 (excluding 6 itself). And 1+2+3 is equal to 6. Therefore, 6 is a perfect number.

Check the perfect number using the for loop

The question is: write a program in Python that checks whether a number is perfect or not using a for loop. Here is its answer:

print("Enter the Number:")
num = int(input())
sum = 0
for i in range(1, num):
  if num%i==0:
    sum = sum+i
if num==sum:
  print("It is a Perfect Number")
else:
  print("It is not a Perfect Number")

Here is its sample run:

Now supply the input, say 6, and press the ENTER key to check and print whether it is a perfect number or not, as shown in the snapshot given below:

Modified version of the previous program

This is the modified version of the previous program, which uses end= and str(). The rest of the program is nearly identical to the previous one. The end= is used to skip the printing of an automatic newline. And str() converts any type into a string type.

print(end="Enter the Number: ")
num = int(input())
sum = 0
for i in range(1, num):
  if num%i==0:
    sum = sum+i
if num==sum:
  print("\n" + str(num) + " is a Perfect Number")
else:
  print("\n" + str(num) + " is not a Perfect Number")

Here is its sample run with user input (496):

Check the perfect number using the while loop

The question is: write a Python program to check for a perfect number using a while loop. Here is its answer:

print(end="Enter the Number: ")
num = int(input())
sum = 0
i = 1
while i<num:
  if num%i==0:
    sum = sum+i
  i = i+1
if num==sum:
  print("\n" + str(num) + " is a Perfect Number")
else:
  print("\n" + str(num) + " is not a Perfect Number")

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