Last Updated: April 13, 2026
Prime Number Checker
Free prime number checker. Test if a number is prime and find nearby primes.
Result
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Nearby Primes
π How We Calculate — Learn about our calculation methodology, data sources, and quality standards.
Frequently Asked Questions
What is a prime number?
A number greater than 1 that has no divisors other than 1 and itself. Examples: 2, 3, 5, 7, 11, 13...
Is 1 prime?
No. By convention, 1 is neither prime nor composite.
How many primes are there?
Infinitely many. Euclid proved this around 300 BC. The largest known prime (2024) has over 41 million digits.