Prime Number Checker
Check whether any integer is a prime number instantly.
How It Works
Enter any positive integer. The tool tests divisibility up to the square root of the number. If no divisor is found, the number is prime.
Formula
A prime has exactly 2 divisors: 1 and itself.
Frequently Asked Questions
Is 1 a prime number?
No. By definition, a prime must have exactly two distinct divisors. 1 has only one divisor (itself), so it is not prime.
What is the smallest prime?
The smallest prime number is 2. It is also the only even prime.