# What is 19 factorial ?

Steps to calculate factorial of 19

## How to calculate the factorial of 19

To find 19 factorial, or 19!, simply use the formula that multiplies the number 19 by all positive whole numbers less than it.

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

19! is exactly : 121645100408832000

Factorial of 19 can be calculated as:
19! = 19 x 18 x 17 x 16 x ... x 3 x 2 x 1

The number of trailing zeros in 19! is 3

The number of digits in 19 factorial is 18.

## What Is Factorial?

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

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

Symbolically, it is showed as "!".

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

## Factorial Formula

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

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

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

We can also measure a factorial from the prior 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 :
19! Factorial = 19 x 18 x 17 x 16 x ... x 3 x 2 x 1 = 19 × 18! = 121645100408832000

## 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 equal to 1. So, 0! = 1.