Factorial of 21 (21!)
RESULT: 51,090,942,171,709,440,000
The factorial of 21, written as 21!, is the product of all positive integers less than or equal to 21.
What Is the Formula to Calculate 21 Factorial?
The formula for calculating 21 factorial (21!) is:
21! = 21 × 20 × 19 × 18 × 17 × 16 × 15 × 14 × 13 × 12 × 11 × 10 × 9 × 8 × 7 × 6 × 5 × 4 × 3 × 2 × 1 = 51,090,942,171,709,440,000
How Many Digits in 21 Factorial?
The number 21! has 19 digits.
Factorial Table From 1! to 21!
| n | n! |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5,040 |
| 8 | 40,320 |
| 9 | 362,880 |
| 10 | 3,628,800 |
Frequently Asked Questions
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What is 21!?
It's the product of all positive integers from 1 to 21. Answer: 51,090,942,171,709,440,000.
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Is factorial defined for negative numbers?
No. Factorials are only defined for non-negative integers (0 and up).
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What is 0!?
By definition, the factorial of 0 is 1.