Prime number checker
Classify an integer as prime, composite or neither.
Formula
A prime has exactly two positive divisors: 1 and itself.
Integer = 97
How to use
- Enter an integer from 0 to 1000000000.
- Read the classification.
- Use prime factorization to investigate a composite.
Examples
- 97 is prime.
- 49 = 7 × 7, so it is composite.
Frequently asked questions
Is 1 prime?
No. It has only one positive divisor; 0 and 1 are neither prime nor composite.
Is 2 prime?
Yes. Its positive divisors are 1 and 2. It is the only even prime.
Is the test probabilistic?
No. Trial division checks all possible prime factors through the square root.
Sources
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