Math & Statistics Tools
Prime Number Checker / Generator
Check if a number is prime and generate prime numbers in a range.
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What is Prime?
A prime number has exactly two factors: 1 and itself. This tool uses trial division for checking and the Sieve of Eratosthenes for generating ranges.
How it works
Prime check: trial division up to sqrt n. Generator: Sieve of Eratosthenes for ranges; incremental trial division for first-N mode.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Realistic sample
Type or paste any realistic input — the tool computes the result locally and instantly.
Common mistakes
Expecting a server round-trip
Nothing is uploaded — every tool in this category runs entirely in your browser.