Prime Number Checker
Check if a number is prime and find prime factors
Nearby Primes
What are Prime Numbers and Why do they Matter?
A prime number is a natural number greater than 1 that has exactly two distinct positive divisors: 1 and itself. Any natural number greater than 1 that is not prime is called a composite number.
Importance in Cryptography
Prime numbers are the "backbone" of modern digital security. Algorithms like RSA rely on the extreme computational difficulty of factoring the product of two very large prime numbers to protect passwords, bank transactions, and private messages across the internet.
How to check if a number is prime?
The most standard method is trial division. To check if a number n is prime, you only need to test divisors from 2 up to the square root of n. If none of these integers divide n evenly, then n is certainly prime.
Mathematical Fun Facts
- The Number 2: It is the only even prime number. All other primes are odd.
- Mersenne Primes: These are primes that follow the form 2n - 1. They are often the largest primes discovered by supercomputers.
- Fundamental Theorem of Arithmetic: Every integer greater than 1 is either a prime itself or can be represented as a unique product of prime numbers.
Privacy & Data Sovereignty
At Octovelo, your data privacy is paramount. Both the prime checking algorithm and the factorization logic run entirely within your web browser. No numbers entered into this tool are ever sent to or stored on our servers.