Math
Prime Number Checker
Enter any positive integer to check if it is prime. For composite numbers, see all divisors listed.
97 is a Prime Number
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Frequently Asked Questions
Quick answers to common questions
What is a prime number?+
A prime number is a natural number greater than 1 that has exactly two divisors: 1 and itself. Examples: 2, 3, 5, 7, 11.
Is 1 a prime number?+
No. By definition, primes must be greater than 1 and have exactly two distinct positive divisors.
Is 2 the only even prime?+
Yes. Every other even number is divisible by 2 and therefore composite.
How large a number can I check?+
The checker works efficiently for numbers up to several million in your browser.