Explore the building blocks of mathematics with our Prime Number Checker. A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.

Prime numbers play a fundamental role in number theory and are the basis of modern cryptography, securing everything from your credit card transactions to your emails.

What is a Prime Number?

• Prime: A number with exactly two factors: 1 and itself (e.g., 2, 3, 5, 7, 11).
• Composite: A number with more than two factors (e.g., 4, 6, 8, 9, 10).
• 1: The number 1 is neither prime nor composite.

Features

• Instant Check: Quickly determine if any number up to 1 trillion is prime.
• Factor Finder: If a number is composite, we list all its factors so you can see why.
• Large Number Support: Capable of handling relatively large integers efficiently.

How to Use

1. Enter a number in the input box.
2. The tool will instantly tell you if it's "PRIME" or "COMPOSITE".
3. If it's composite, review the list of factors below.

Fun Fact

The number 2 is the only even prime number. All other even numbers can be divided by 2, making them composite.