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Prime Number Checker

Check if a number is prime and generate a list of primes up to any value.

Enter any number to instantly find out if it's prime, see its factors if it's composite, and discover the nearest prime numbers above and below it. Great for math students, number theory enthusiasts, and quick verifications.

Features

Prime Test
Instantly determine if a number is prime or composite.
Factor List
For composite numbers, see all prime factors.
Nearest Primes
Find the closest prime numbers above and below your input.
Instant Result
Check any number in milliseconds.

How to Check

  1. Enter any positive integer in the input field.
  2. The result appears instantly: Prime or Composite.
  3. For composite numbers, the prime factorization is shown.

FAQ

Is 1 a prime number?

No. By definition, prime numbers must have exactly two distinct divisors (1 and themselves). The number 1 has only one divisor.

What is the largest prime this tool can check?

The tool uses efficient algorithms and can handle very large numbers, though extremely large inputs may take a moment.

Prime Number Facts

  • 2 is the only even prime number.
  • There are infinitely many prime numbers (proven by Euclid ~300 BC).
  • The largest known prime (as of 2024) has over 41 million digits.

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