What is 20 factorial ?

To find 20 factorial, or 20!, simply use the formula that multiplies the number 20 by all positive whole numbers less than it.

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

  20! is exactly : 2432902008176640000

  Factorial of 20 can be calculated as:
20! = 20 x 19 x 18 x 17 x ... x 3 x 2 x 1

  The number of trailing zeros in 20! is 4

  The number of digits in 20 factorial is 19.

• 16 Factorial
• 17 Factorial
• 18 Factorial
• 19 Factorial
• Factorial of 21
• Factorial of 22
• Factorial of 23
• Factorial of 24

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

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

Symbolically, it is showed as "!".

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

To find the factorial of any given number, alternate the value for n in the given equation :

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

The expansion of the formula gives the numbers to be multiplied together to have the factorial of the number.

We can also calculate 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 :
20! Factorial = 20 x 19 x 18 x 17 x ... x 3 x 2 x 1 = 20 × 19! = 2432902008176640000

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"

20 in French

20 in English

Factors of 20