🔢 Prime Number Calculator

Check if any number is prime and find its complete prime factorization instantly.

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First 50 prime numbers

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229

Frequently asked questions

Is 1 a prime number?

No. By definition, prime numbers must have exactly two distinct divisors — 1 and themselves. The number 1 only has one divisor, so it is neither prime nor composite.

Is 2 the only even prime?

Yes. Every even number greater than 2 is divisible by 2, so it cannot be prime. 2 is the only even prime number.

What are prime numbers used for?

Prime numbers are fundamental to modern cryptography. The security of HTTPS, SSL and most internet encryption relies on the mathematical difficulty of factoring very large numbers into their prime factors.