Prime Number Calculator
Check whether a number is prime and, if not, show its factorization. Enter your values, click Calculate, and get the full result with its breakdown — everything is processed on your device, nothing is sent to a server.
All calculations run in your browser. Your data is never sent to our servers.
Example
Example Input
561
Example Output
not prime — 3 × 11 × 17
How to Use
- 1Fill in each input field with the values you want to compute.
- 2If there are choices (units, mode, operation), pick what you need.
- 3Click the Calculate button (or press Ctrl+Enter).
- 4The main result and its breakdown appear in the Result area. Click Copy to copy it.
About the Prime Number Calculator
The Prime Number Calculator tests primality using a deterministic Miller–Rabin test that is fast and reliable for large ranges. If the number is not prime (and small enough), its prime factors are shown.
Useful for number theory, cryptography, and math practice.
FAQ
Is this Prime Number Calculator accurate?
Yes. It uses standard formulas and runs directly in your browser at full JavaScript precision (plus BigInt/decimal.js for large numbers where needed).
Is my data sent to a server?
No. All calculations happen entirely on your device. No values are sent to or stored on our servers.