Prime Number Checker
One entry per line - check primality, list primes in a range, or find the Nth prime
Mode:   Max results:   Separator:
Calculation Result Download CSV
No. Value Result Detail

Introduction to the tool and how to use it

Test primality, generate prime lists and look up the Nth prime - three common jobs in one box, one entry per line.

How to use:
1. Pick a mode:
   - Check: one integer per line, e.g. 97;
   - List: one range per line, e.g. 100,200;
   - Nth prime: one index per line, e.g. 1000;
2. Hit Run to get the verdict, the number of primes or the Nth prime;
3. Copy the result or export it as CSV.

Composites come with their smallest prime factor (360 = 2 x 180) while primes are marked as yes. Big integers are tested with BigInt plus Miller-Rabin (deterministic below 2^64), and ranges use a sieve of Eratosthenes that answers instantly below 5,000,000.

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