Given a positive integer N., The task is to find the value of where function F(i) for the number i be defined as the sum of all divisors of ‘i‘.
Example 1:
Input:
N = 4
Output:
15
Explanation:
F(1) = 1
F(2) = 1 + 2 = 3
F(3) = 1 + 3 = 4
F(4) = 1 + 2 + 4 = 7
ans = F(1) + F(2) + F(3) + F(4)
= 1 + 3 + 4 + 7
= 15
Example 2:
Input:
N = 5
Output:
21
Explanation:
F(1) = 1
F(2) = 1 + 2 = 3
F(3) = 1 + 3 = 4
F(4) = 1 + 2 + 4 = 7
F(5) = 1 + 5 = 6
ans = F(1) + F(2) + F(3) + F(4) + F(5)
= 1 + 3 + 4 + 7 + 6
= 21
Your Task:
You don't need to read input or print anything. Your task is to complete the function sumOfDivisors() which takes an integer N as an input parameter and returns the answer of the problem asked.
Expected Time Complexity: O(N)
Expected Auxiliary Space: O(1)
Constraints:
1 <= N <= 10^{6}

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