What is 21 factorial?

21! = 51090942171709440000.... It has 20 digits and 4 trailing zeros.

Calculate the factorial of 21 - Factorial Calculator

Quick Answer: 21! = 5109094217...0000
20 digits | 4 trailing zeros

Factorial Calculator Until 10,000

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21! Result

51090942171709440000...09440000

How 21! is calculated

The number of trailing zeros in 21! is 4.
The number of digits in 21 factorial is 20.
The factorial of 21 is calculated, through its definition, this way:
21! = 21 • 20 • 19 • 18 • 17 ... 3 • 2 • 1

Exact value of 21!

21! = 51090942171709440000

Nearby Factorials

n	n!	Digits	Trailing Zeros
16!	20922789888000	14	3
17!	355687428096000	15	3
18!	6402373705728000	16	3
19!	121645100408832000	18	3
20!	2432902008176640000	19	4
21!	51090942...0000	20	4
22!	11240007...0000	22	4
23!	25852016...0000	23	4
24!	62044840...0000	24	4
25!	15511210...0000	26	6
26!	40329146...0000	27	6

More factorial calculations

Here you can find answers to questions like: Calculate the factorial of 21 What is the factorial of 21? What is the last digits of factorial of 21? How many trailing zeros in 21 factorial? How many digits are there in 21 factorial? Use the factorial calculator above to find the factorial of any natural between 0 and 10,000.

What is factorial?

Definition of factorial

The factorial is a quantity defined for any integer n greater than or equal to 0.

The factorial is the product of all integers less than or equal to n but greater than or equal to 1. The factorial value of 0 is, by definition, equal to 1. For negative integers, factorials are not defined. The factorial can be seen as the result of multiplying a sequence of descending natural numbers (such as 3 × 2 × 1).

The factorial symbol is the exclamation mark (!).

The factorial formula

If n is a natural number greater than or equal to 1, then

n! = n x (n - 1) x (n - 2) x (n - 3) ... 3 x 2 x 1

If n = 0, then n! = 1, by convention.

Example: 6! = 6 x 5 x 4 x 3 x 2 x 1 = 720

Shortcut to find trailing zeros in a factorial

Trailing zeros are a sequence of zeros in the decimal representation of a number, after which no other digits follow. This video shows how to find the trailing zeros of a factorial easily.

Table of factorials until 30

n	n!
1!	1	#
2!	2	#
3!	6	#
4!	24	#
5!	120	#
6!	720	#
7!	5040	#
8!	40320	#
9!	362880	#
10!	3628800	#
11!	39916800	#
12!	479001600	#
13!	6227020800	#
14!	87178291200	#
15!	1307674368000	#
16!	20922789888000	#
17!	355687428096000	#
18!	6402373705728000	#
19!	121645100408832000	#
20!	2432902008176640000	#
21!	51090942171709440000	#
22!	1124000727777607680000	#
23!	25852016738884976640000	#
24!	620448401733239439360000	#
25!	15511210043330985984000000	#
26!	403291461126605635584000000	#
27!	10888869450418352160768000000	#
28!	304888344611713860501504000000	#
29!	8841761993739701954543616000000	#
30!	265252859812191058636308480000000	#

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Trailing Zeros in Factorials

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