# Maximum sum of distinct numbers such that LCM of these numbers is N

Given a positive number N. The task is to find maximum sum of distinct numbers such that the LCM of all these numbers is equal to N.

Examples:

```Input  : 2
Output : 3
The distinct numbers you can have are
just 1 and 2 and their sum is equal to 3.

Input  : 5
Output : 6
```

## Recommended: Please solve it on “PRACTICE” first, before moving on to the solution.

As the LCM of all the numbers is N. So all the numbers must be the divisors of N and all the numbers are distinct so answer must be the sum of all the divisors of N. To find all the divisors efficiently refer to article https://www.geeksforgeeks.org/find-all-divisors-of-a-natural-number-set-2/

## C++

 `// C++ program to find the max sum of ` `// numbers whose lcm is n ` `#include ` `using` `namespace` `std; ` ` `  `// Returns maximum sum of numbers with ` `// LCM as N ` `int` `maxSumLCM(``int` `n) ` `{ ` `    ``int` `max_sum = 0;  ``// Initialize result ` ` `  `    ``// Finding a divisor of n and adding ` `    ``// it to max_sum ` `    ``for` `(``int` `i=1; i*i<=n; i++) ` `    ``{ ` `        ``if` `(n%i == 0) ` `        ``{ ` `            ``max_sum += i; ` `            ``if` `(n/i != i) ` `                ``max_sum += (n/i); ` `        ``} ` `    ``} ` ` `  `    ``return` `max_sum; ` `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``int` `n = 2; ` `    ``cout << MaxSumLCM(n) << endl; ` `    ``return` `0; ` `} `

## Java

 `// Java program to find the max sum of ` `// numbers whose lcm is n ` ` `  `class` `MaxSum ` `{ ` `    ``// Returns maximum sum of numbers with ` `    ``// LCM as N ` `    ``static` `int` `maxSumLCM(``int` `n) ` `    ``{ ` `        ``int` `max_sum = ``0``;  ``// Initialize result ` `      `  `        ``// Finding a divisor of n and adding ` `        ``// it to max_sum ` `        ``for` `(``int` `i=``1``; i*i<=n; i++) ` `        ``{ ` `            ``if` `(n%i == ``0``) ` `            ``{ ` `                ``max_sum += i; ` `                ``if` `(n/i != i) ` `                    ``max_sum += (n/i); ` `            ``} ` `        ``} ` `         `  `        ``return` `max_sum; ` `    ``} ` `     `  `    ``// main function ` `    ``public` `static` `void` `main (String[] args)  ` `    ``{ ` `        ``int` `n = ``2``; ` `        ``System.out.println(maxSumLCM(n)); ` `    ``} ` `} `

## Python3

 `# Python3 program to find the max sum of ` `# numbers whose lcm is n ` ` `  `# Returns maximum sum of numbers with ` `# LCM as N ` `def` `maxSumLCM(n) : ` `     `  `    ``# Initialize result ` `    ``max_sum ``=` `0`  ` `  `    ``# Finding a divisor of n and adding ` `    ``# it to max_sum ` `    ``i ``=` `1` `    ``while``(i ``*` `i<``=` `n ): ` `        ``if` `(n ``%` `i ``=``=` `0``) : ` `            ``max_sum ``=` `max_sum ``+` `i ` `            ``if` `(n ``/``/` `i !``=` `i) : ` `                ``max_sum ``=` `max_sum ``+` `(n ``/``/` `i) ` `        ``i ``=` `i ``+` `1` `     `  `    ``return` `max_sum ` ` `  `# Driver code ` `n ``=` `2` `print``(maxSumLCM(n)) ` ` `  `# This code is contributed by Nikita Tiwari. `

Output:

```3
```

## C#

 `// C# program to find the max sum  ` `// of numbers whose lcm is n ` `using` `System; ` ` `  `class` `MaxSum ` `{ ` `     `  `    ``// Returns maximum sum of   ` `    ``// numbers with LCM as N ` `    ``static` `int` `maxSumLCM(``int` `n) ` `    ``{ ` `         `  `         ``// Initialize result ` `         ``int` `max_sum = 0; ` `     `  `        ``// Finding a divisor of n and  ` `        ``// adding it to max_sum ` `        ``for` `(``int` `i = 1; i * i <= n; i++) ` `        ``{ ` `            ``if` `(n % i == 0) ` `            ``{ ` `                ``max_sum += i; ` `                ``if` `(n / i != i) ` `                    ``max_sum += (n / i); ` `            ``} ` `        ``} ` `         `  `        ``return` `max_sum; ` `    ``} ` `     `  `    ``// Driver Code ` `    ``public` `static` `void` `Main (String[] args)  ` `    ``{ ` `        ``int` `n = 2; ` `        ``Console.Write(maxSumLCM(n)); ` `    ``} ` `} ` ` `  `// This code is contributed by parashar.. `

## PHP

 ` `

Output:

`3`

This article is contributed by Ayush Jha. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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Improved By : parashar, jit_t