Prime Checker
Trial-division primality for integers up to 1,000,000,000,000 in absolute value.
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How to use Prime Checker
- Enter integer. Leave a field blank only when the page says the value is missing, not by typing 0 unless 0 is a real value.
- Read the result rows under the form. Errors appear in the status line. Nothing is uploaded.
- Rounding follows IEEE floating point in this browser unless the page says it uses integers or BigInt.
Prime Checker
Prime check
| Computes | Trial-division primality for integers up to 1,000,000,000,000 in absolute value. |
|---|---|
| Includes | Prime check |
| Includes | Trial division |
| Engine | percentage |
| Upload | None |
| Advice | Arithmetic only |
What Prime Checker is
Negatives, 0, and 1 are not prime. Evens other than 2 are composite. Trial division tests odd divisors up to sqrt(n).
The formula runs in this tab. CZNull does not receive the numbers.
How this page computes
Factorization is prime factors. This page does not run Miller-Rabin; it is exact trial division in the stated range.
Entities and related jobs
Trial-division primality for integers up to 1,000,000,000,000 in absolute value. Named features: Prime check, Trial division.
See also Prime Factorization, GCD Calculator, Factorial Calculator, Percentage Calculator, Scientific Calculator, Fraction Calculator.
Use cases
Homework and small cryptography demos. It is not a 2048-bit primality service.
Limits
Invalid input appears in the status line. IEEE floating point applies unless a row says otherwise. CZNull does not receive the numbers.