What Is Prime Number Calculator?
The Prime Number Calculator works in three modes: check and factorize a single number, look up the k-th prime, or list every prime between two bounds. A check gives a plain prime or composite verdict, the full factorization written as primes with exponents, the number of divisors, whether the number is a perfect square or a palindrome, and the primes immediately before and after it. Primality is decided by deterministic Miller-Rabin, so the answer is exact across the whole 64-bit range rather than probably prime.
Who Uses the Prime Number Calculator?
Students and maths teachers use it to test a number and read its structure, while developers and competitive programmers use it to get the k-th prime or a screened range without writing a trial division loop.
How to Use the Prime Number Calculator
- Pick a mode: Check and Factorize for one number, Nth Prime to find a prime by position, or Primes in Range to screen everything between two bounds.
- Enter the number in the Number N field and press Check Number, or type a position starting at 1 in the Position k field, or fill in the Lowest value and Highest value fields and press the matching button.
- Read the verdict, the prime factorization with its exponents, the divisor count, the perfect square and palindrome checks and the neighbouring primes, or the list of primes found with a count.
Why Choose Our Prime Number Calculator?
- Deterministic Miller-Rabin makes the verdict exact for 64-bit integers, not a probable result that can be wrong
- Three jobs in one tool: a verdict and factorization, the k-th prime, and a complete list of primes inside a range
- Divisor count, perfect square and palindrome tests come out of the same factorization, which saves working them out by hand
- Runs on your own device, so a large candidate or a private key value is never sent anywhere
Try the Prime Number Calculator above — it is free, fast, and works on any device. Bookmark this page to return whenever you need it.