# What is 13 factorial ?

Steps to calculate factorial of 13

## How to calculate the factorial of 13

To find 13 factorial, or 13!, simply use the formula that multiplies the number 13 by all positive whole numbers less than it.

Let's look at how to calculate the Factorial of Thirteen :

13! is exactly : 6227020800

Factorial of 13 can be calculated as:
13! = 13 x 12 x 11 x 10 x ... x 3 x 2 x 1

The number of trailing zeros in 13! is 2

The number of digits in 13 factorial is 10.

## What Is Factorial?

A factorial is represented by an integer and an exclamation mark. In arithmetic, factorial is a multiplication process of natural numbers .

It multiplies the number by every organic number that is less than it .

Symbolically, it is represented as "!".

The function is used, among other things, to get the "n" way items can be determined .

## Factorial Formula

To find the factorial of any given number, replace the value for n in the given solution :

n! = n × (n-1) × (n-2) × (n-3) × ….× 3 × 2 × 1

The expansion of the formula provides the numbers to be multiplied to each other to have the factorial of the number.

We can also work out a factorial from the previous one. The factorial of any number is that number replicated the factorial of (that number minus 1).

So the rule is : n! = n × (n−1)!

Example :
13! Factorial = 13 x 12 x 11 x 10 x ... x 3 x 2 x 1 = 13 × 12! = 6227020800

## What are Factorials Used For?

The best use of factorial is in Combinations and Permutations.

Example : Determine how to arrange letters without repeating?

There one way for 1 letter "a":
2 ways for two letters "ab": ab, ba.
There are 6 ways for 3 letters "abc": abc acb cab bac bca.
There are 24 ways for 1234 of the letters "abcd"

## Frequently Asked Questions on Factorial

### Can we have factorials for negative numbers ?

Negative integer factorials are undefined

### What Is 0!

Zero factorial or Factorial of 0 is simple, and its value is corresponding to 1. So, 0! = 1.