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

Prime checker and generator: one input box handles three common needs, one entry per line, many lines at once.
Composite numbers show their smallest prime factor (for example 360 = 2 × 180), while primes are marked yes. Large integers use BigInt plus Miller-Rabin (deterministic below 2^64), so no floating-point error; range mode uses the Sieve of Eratosthenes and returns instantly up to 5 000 000.

How to use

  1. Choose a mode:
       · Check primality: one integer per line, such as 97;
       · Generate a prime list: one range per line, such as 100,200;
       · Nth prime: one index per line, such as 1000.
  2. Click start calculation; the result table shows the verdict, prime count, or the Nth prime.
  3. Results can be copied with one click and exported as CSV.
Prime test

Primes between 1000 and 1100

Between 1000 and 1100 there are 16 primes, from 1009 up to 1097.

  • Range1000 ~ 1100
  • Divisors16
  • Smallest prime in range1009
  • Largest prime in range1097
Primes in range
#Prime
11009
21013
31019
41021
51031
61033
71039
81049
91051
101061
111063
121069
131087
141091
151093
161097
  • Large numbers are decided with Miller-Rabin (12 bases), which is deterministic below 2^64.

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