# Ways to express a number as product of two different factors

• Difficulty Level : Easy
• Last Updated : 23 Jun, 2022

Given a number n, write a program to calculate the number of ways in which numbers can be expressed as the product of two different factors.

Examples:

```Input : 12
Output : 3
12 can be expressed as 1 * 12, 2 * 6 and 3*4.

Input : 36
Output : 4
36 can be expressed as 1 * 36, 2 * 18, 3 * 12 and 4 * 9.```
```All factors of 12 are = 1, 2, 3, 4, 6, 12

We can observe that factors always exist in
pair which is equal to number.

Here (1, 12), (2, 6) and (3, 4) are such pairs.```

As a number can be expressed as the product of two factors we only need to find the number of factors of number up to the square root of the number. And we only need to find only different pairs so in the case of a perfect square we don’t include that factor.

## C++

 `// CPP program to find number of ways``// in which number expressed as``// product of two different factors``#include ``using` `namespace` `std;` `// To count number of ways in which``// number expressed as product``// of two different numbers``int` `countWays(``int` `n)``{``    ``// To store count of such pairs``    ``int` `count = 0;` `    ``// Counting number of pairs``    ``// upto sqrt(n) - 1``    ``for` `(``int` `i = 1; i * i < n; i++)``        ``if` `(n % i == 0)``            ``count++;` `    ``// To return count of pairs``    ``return` `count;``}` `// Driver program to test countWays()``int` `main()``{``    ``int` `n = 12;``    ``cout << countWays(n) << endl;``    ``return` `0;``}`

## Java

 `// Java program to find number of ways``// in which number expressed as``// product of two different factors``public` `class` `Main {` `    ``// To count number of ways in which``    ``// number expressed as product``    ``// of two different numbers``    ``static` `int` `countWays(``int` `n)``    ``{``        ``// To store count of such pairs``        ``int` `count = ``0``;` `        ``// Counting number of pairs``        ``// upto sqrt(n) - 1``        ``for` `(``int` `i = ``1``; i * i < n; i++)``            ``if` `(n % i == ``0``)``                ``count++;` `        ``// To return count of pairs``        ``return` `count;``    ``}` `    ``// Driver program to test countWays()``    ``public` `static` `void` `main(String[] args)``    ``{``        ``int` `n = ``12``;``        ``System.out.println(countWays(n));``    ``}``}`

## Python 3

 `# Python 3 program to find number of ways``# in which number expressed as``# product of two different factors` `# To count number of ways in which``# number expressed as product``# of two different numbers``def` `countWays(n):``    ` `    ``# To store count of such pairs``    ``count ``=` `0``    ``i ``=` `1``    ` `    ``# Counting number of pairs``    ``# upto sqrt(n) - 1``    ``while` `((i ``*` `i)

## C#

 `// C# program to find number of ways``// in which number expressed as``// product of two different factors``using` `System;` `public` `class` `main {` `    ``// To count number of ways in which``    ``// number expressed as product``    ``// of two different numbers``    ``static` `int` `countWays(``int` `n)``    ``{` `        ``// To store count of such pairs``        ``int` `count = 0;` `        ``// Counting number of pairs``        ``// upto sqrt(n) - 1``        ``for` `(``int` `i = 1; i * i < n; i++)``            ``if` `(n % i == 0)``                ``count++;` `        ``// To return count of pairs``        ``return` `count;``    ``}` `    ``// Driver program to test countWays()``    ``public` `static` `void` `Main()``    ``{``        ``int` `n = 12;` `        ``Console.WriteLine(countWays(n));``    ``}``}` `// This code is contributed by Anant Agarwal.`

## PHP

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## Javascript

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Output:

`3`

Time Complexity: O(√n)
Auxiliary Space: O(1)

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