Factorial Calculator
Easily calculate the factorial of any number
Enter a number between 0 and 1000
Common Factorials:
0!
1
0! = 1 (by definition)
5!
120
5! = 5×4×3×2×1 = 120
10!
3628800
10! = 3,628,800
12!
479001600
12! = 479,001,600
20!
2432902008176640000
20! (huge number)
About Factorials
The factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n.
n! = n × (n-1) × (n-2) × ... × 3 × 2 × 1
0! = 1 (by convention)
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0! = 1 by definition (empty product)
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Factorial grows faster than exponential functions
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n! has approximately n/2 digits
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Stirling's approximation: n! ≈ √(2πn)(n/e)ⁿ
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Factorials are used in permutations and combinations
Frequently Asked Questions (FAQs)
The factorial of a non-negative integer n, denoted by n!, is the product of all positive integers less than or equal to n.
By definition, the factorial of 0 is 1.
Factorials are widely used in mathematics, probability, statistics, permutations, and combinations.
No, factorial is only defined for non-negative integers.
5! (5 factorial) = 5 × 4 × 3 × 2 × 1 = 120.
