# What is 65 factorial ?

Steps to calculate factorial of 65

## How to calculate the factorial of 65

To find 65 factorial, or 65!, simply use the formula that multiplies the number 65 by all positive whole numbers less than it.

Let's look at how to calculate the Factorial of Sixty-five :

65! is exactly : 8247650592082470666723170306785496252186258551345437492922123134388955774976000000000000000

Factorial of 65 can be calculated as:
65! = 65 x 64 x 63 x 62 x ... x 3 x 2 x 1

The number of trailing zeros in 65! is 15

The number of digits in 65 factorial is 91.

## What Is Factorial?

A factorial is displayed by an integer and an exclamation symbol. In Mathematics, factorial is a multiplication procedure of natural numbers .

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

Symbolically, it is displayed as "!".

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

## 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 shows the numbers to be multiplied with each other to have the factorial of the number.

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

So the rule is : n! = n × (n−1)!

Example :
65! Factorial = 65 x 64 x 63 x 62 x ... x 3 x 2 x 1 = 65 × 64! = 8247650592082470666723170306785496252186258551345437492922123134388955774976000000000000000

## 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 number factorials are undefined

### What Is 0!

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