Prime Number Calculator

Use our free prime number calculator to test if a number is prime, find the nearest prime, or list all primes in a range.

Math

Mode

Number

Start

End

Formula

A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. 2 is the smallest prime number.

A prime number has exactly two distinct positive divisors: 1 and itself.

Percentage: The percentage value you want to apply

Number: The original number or value

Result: The calculated result

How It Works

1Choose a mode: Check, Nearest Prime, or List Primes in Range.
2For Check/Nearest, enter a number. For Range, enter start and end values.
3Click Calculate to see the result.

Examples

Check 17

1.17 has divisors 1 and 17 only
2.17 is prime

Result: Is prime

Nearest prime to 18

1.Previous prime: 17
2.Next prime: 19
3.Nearest: 17 and 19 (tie)

Result: 17, 19

Primes 10-50

1.Primes: 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47

Result: 11 primes

Frequently Asked Questions

A number with exactly two distinct divisors: 1 and itself.

No, 1 has only one divisor and is neither prime nor composite.

Yes, 2 is the smallest and only even prime number.

There is no largest prime; they go on forever (Euclid's theorem).

It tests divisibility up to the square root of the number.

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Prime Factorization Calculator Factors Calculator LCM Calculator Multiples Calculator Percentage Calculator Basic Calculator

CalculateMe Team

Last updated: 2026-07-14

Prime Number Calculator

Formula

How It Works

Examples

Check 17

Nearest prime to 18

Primes 10-50

Frequently Asked Questions

What is a prime number?

Is 1 prime?

Is 2 prime?

What is the largest known prime?

How does the checker work?

Related Calculators

Prime Number Calculator

Formula

How It Works

Examples

Check 17

Nearest prime to 18

Primes 10-50

Frequently Asked Questions

What is a prime number?

Is 1 prime?

Is 2 prime?

What is the largest known prime?

How does the checker work?

Related Calculators