Factorial Calculator

n! for large n using BigInt — exact value plus scientific.

Calculator Numbers & Math Updated Apr 19, 2026
n
n!

Notes

Definition
n! = n × (n−1) × ... × 2 × 1
0!
= 1 (by convention)
Stirling
n! ≈ √(2πn) · (n/e)^n

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