Prime Number Checker
Test positive integers up to one billion for prime-number status locally.
Loading the local tool workspace…
What is Prime Number Checker?
Prime Number Checker tests whether a positive integer has exactly two positive divisors.
How to use Prime Number Checker
- 01
Enter a whole number from 1 through 1,000,000,000.
- 02
Change the number to test another candidate.
- 03
Read whether the value is prime or composite.
Prime Number Checker FAQ
Does the tool query an online prime database?
No. It performs a deterministic divisibility test locally in your browser.
Is Prime Number Checker private to use?
Yes. Number parsing, statistics, conversions and random generation all run locally in your browser.