Enter any whole number and the tool reports whether it is prime and shows the nearest prime numbers on either side.
A prime number greater than 1 has exactly two divisors: 1 and itself, so it cannot be evenly divided by any other number.
The checker tests divisibility by integers up to the square root of the number — enough to confirm primality efficiently.
No — 1 has only a single divisor, so by definition it is neither prime nor composite.