# Python Program for Find sum of even factors of a number

In this article, we will learn about the solution to the problem statement given below −

## Problem statement

Given a number input n, the task is to Find the sum of even factors of a number.

Here we first need to eliminate all the odd factors.

If the number input is odd it has no even factors therefor return zero directly , otherwise, we will follow the approach in the code below

Below is the implementation −

## Example

Live Demo

import math
# Returns sum of all even factors of n.
def sumofFactors(n) :
# If n is odd
if (n % 2 != 0) :
return 0
#all prime factors
res = 1
for i in range(2, (int)(math.sqrt(n)) + 1) :
count = 0
curr_sum = 1
curr_term = 1
while (n % i == 0) :
count= count + 1
n = n // i
# here we remove the 2^0 that is 1. All other factors
if (i == 2 and count == 1) :
curr_sum = 0
curr_term = curr_term * i
curr_sum = curr_sum + curr_term
res = res * curr_sum
# if n is prime number
if (n >= 2) :
res = res * (1 + n)
return res
# main
n = 20
print(sumofFactors(n))

## Output

36

All the variables are declared in the global frame as shown in the figure given below −

## Conclusion

In this article, we learned about the approach to Find the sum of even factors of a number