Prime Checker

How the Prime Checker Works

This calculator determines whether a number is prime, composite, or neither. It uses efficient divisibility rules and checks only up to the square root of the number for maximum performance.

Formulas & Rules Used

The calculator uses standard prime‑number rules:

• Prime Definition: A number greater than 1 with exactly two factors: 1 and itself.
• Composite: A number with more than two factors.
• Neither: 0 and 1 are not prime or composite.
• Divisibility Check: Test divisors only up to √n.

Example

Check if 29 is prime:

√29 ≈ 5.38
Check divisors: 2, 3, 5
29 is not divisible by any of them

Result: 29 is a prime number