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Perfect Number
- Any number can be perfect number, if the sum of its positive divisors excluding the number itself is equal to that number.
- For example, 6 is a perfect number because 6 is divisible by 1, 2, 3 and 6.
- So, the sum of these values are: 1+2+3 = 6 (Remember, we have to exclude the number itself.
- That’s why we haven’t added 6 here). Some of the perfect numbers are 6, 28, 496, 8128 and 33550336 so on.
- How to write a Python program to find Perfect Number using For Loop, While Loop, and Functions.
Learn Python - Python tutorial - Python Program to find Perfect Number - Python examples - Python programs
Python Program to find Perfect Number using For loop
- This Python program allows the user to enter any number.
- Using this number it will calculate whether the number is Perfect number or not using the Python For Loop.
Sample Code
# Python Program to find Perfect Number using For loop
Number = int(input(" Please Enter any Number: "))
Sum = 0
for i in range(1, Number):
if(Number % i == 0):
Sum = Sum + i
if (Sum == Number):
print(" %d is a Perfect Number" %Number)
else:
print(" %d is not a Perfect Number" %Number)click below button to copy the code. By Python tutorial team
Analysis
- Following statement will ask the user to enter any number and stores the user entered value in variable Number
Number = int(input(" Please Enter any Number: "))click below button to copy the code. By Python tutorial team
- Next line, We declared integer variable Sum = 0.
- Next, we used the for loop with range() and we are not going to explain the for loop here.
- If you don’t understand for loop then please visit our article Python For Loop.
for i in range(1, Number):click below button to copy the code. By Python tutorial team
- Inside the For loop we placed Python If Statement to test the condition
if(Number % i == 0):
Sum = Sum + iclick below button to copy the code. By Python tutorial team
- If statement inside the for loop will check whether the Number is Perfectly divisible by i value or not.
- f the Number is perfectly divisible by i then i value will be added to the Sum.
Output
Learn Python - Python tutorial - Python Program to find Perfect Number using For loop - Python examples - Python programs
- From the above Screenshot, User Entered value is: Number = 6
First Iteration
For the first Iteration, Number = 6, Sum = 0 and i = 1 If (Number % i == 0) 6 % 1 == 0 If statement is succeeded here So, Sum = Sum + i Sum = 0 +1 = 1
Second Iteration
For the second Iteration the values of both Sum and i has been changed as: Sum = 1 and i = 2 If (Number % i == 0) 6 % 2 == 0 If statement is succeeded here So, Sum = Sum + i Sum = 1 + 2 = 3
Third Iteration
For the third Iteration the values of both Sum and i has been changed as: Sum = 3 and i = 3 If (Number % i == 0) 6 % 3 == 0 If statement is succeeded here So, Sum = Sum + i Sum = 3 + 3 = 6 For the fourth and fifth iterations condition inside the if condition will fail 6 % 4 == 0 (FALSE) 6 % 5 == 0 (FALSE)
- So, compiler will terminate the for loop.
- In the next line we have If statement to check whether the value inside the Sum variable is exactly equal to given Number or Not.
- If the condition (Sum == Number) is TRUE then below print statement will be executed
print(" %d is a Perfect Number" %Number)click below button to copy the code. By Python tutorial team
- If the condition (Sum == Number) is FALSE then below print statement will be executed
print(" %d is not a Perfect Number" %Number)click below button to copy the code. By Python tutorial team
- For this example (Sum == Number) is True. So, given Number is Perfect Number
Python Program to find Perfect Number using While Loop
- This program allows the user to enter any number. Using this number it will calculate whether the user input is Perfect number or not using Python While loop.
Sample Code
# Python Program to find Perfect Number using While loop
Number = int(input(" Please Enter any Number: "))
i = 1
Sum = 0
while(i < Number):
if(Number % i == 0):
Sum = Sum + i
i = i + 1
if (Sum == Number):
print(" %d is a Perfect Number" %Number)
else:
print(" %d is not the Perfect Number" %Number)click below button to copy the code. By Python tutorial team
- We haven’t done anything special in this example.
- We just replaced the For loop with While Loop and if you find difficult to understand the While loop functionality
Output
Learn Python - Python tutorial - Python Program to find Perfect Number using While Loop - Python examples - Python programs
Python Program to find Perfect Number using Function
- This program allows the user to enter any number.
- Using this number it will calculate whether the number is Perfect number or not using the Functions.
Sample Code
# Python Program to find Perfect Number using Functions
def Perfect_Number(Number):
Sum = 0
for i in range(1, Number):
if(Number % i == 0):
Sum = Sum + i
return Sum
# Taking input from the user
Number = int(input("Please Enter any number: "))
if (Number == Perfect_Number(Number)):
print("\n %d is a Perfect Number" %Number)
else:
print("\n %d is not a Perfect Number" %Number)click below button to copy the code. By Python tutorial team
- If you observe the above code, We haven’t done anything special in this example.
- We just defined the new user defined function and added the code we mentioned in For loop example.
Output
Learn Python - Python tutorial - Python Program to find Perfect Number using Function - Python examples - Python programs
Python Program to Find Perfect Number between 1 to 1000
- This program allows the user to enter minimum and maximum values. This program will find the Perfect Number between the Minimum and Maximum values.
# Python Program to find Perfect Number between 1 to 1000
# Taking input from the user
Minimum = int(input("Please Enter any Minimum Value: "))
Maximum = int(input("Please Enter any Maximum Value: "))
# initialise sum
# Checking the Perfect Number
for Number in range(Minimum, Maximum - 1):
Sum = 0
for n in range(1, Number - 1):
if(Number % n == 0):
Sum = Sum + n
# display the result
if(Sum == Number):
print(" %d " %Number)click below button to copy the code. By Python tutorial team
Output
Learn Python - Python tutorial - Python Program to Find Perfect Number between 1 to 1000 - examples - programs
Analysis
- This For Loop helps compiler to iterate between Minimum and Maximum Variables, iteration starts at the Minimum and then it will not exceed Maximum variable.
for Number in range(Minimum, Maximum):