mathjs/docs/reference/functions/factorial.md

Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser and offers an integrated solution to work with numbers, big numbers, complex numbers, units, and matrices.

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# Function factorial

Compute the factorial of a value

Factorial only supports an integer value as argument.
For matrices, the function is evaluated element wise.


## Syntax

```js
math.factorial(n)
```

### Parameters

Parameter | Type | Description
--------- | ---- | -----------
`n` | number &#124; BigNumber &#124; Array &#124; Matrix | An integer number

### Returns

Type | Description
---- | -----------
number &#124; BigNumber &#124; Array &#124; Matrix | The factorial of `n`


## Examples

```js
math.factorial(5);    // returns 120
math.factorial(3);    // returns 6
```


## See also

[combinations](combinations.md),
[gamma](gamma.md),
[permutations](permutations.md)