Prime Number Checker
Prime Number Checker
A prime number has exactly two factors: 1 and itself. This checker determines whether a number is prime and lists all its factors.
Conversion Formula
To check primality, test divisibility by all integers from 2 to √n. If none divide evenly, the number is prime.
Step-by-Step Examples
97 = Prime: Yes, Factors: 1, 97
97 has no divisors other than 1 and itself.
100 = Prime: No, Factors: 1, 2, 4, 5, 10, 20, 25, 50, 100
100 has many factors, so it is composite.
Frequently Asked Questions
What is a prime number?
A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself.
Is 1 a prime number?
No. By definition, prime numbers must be greater than 1. The number 1 is neither prime nor composite.
Is 2 a prime number?
Yes. 2 is the only even prime number. Every other even number is divisible by 2, so not prime.
How many prime numbers are there?
Infinitely many. Euclid proved this around 300 BC. There is no largest prime number.
Why are prime numbers important?
Primes are the building blocks of all integers (Fundamental Theorem of Arithmetic). They are also critical in cryptography, especially RSA encryption.