Prime Checker & Factorization Tool
Enter an integer to check whether it is prime and see its prime factorization.
Enter an integer
How to Use
1
Enter an integer
Type the integer you want to check. Natural numbers of 2 or greater are supported.
2
Click "Check"
Press the button to see whether the number is prime and its factorization.
3
Review and copy
Copy the factorization with one click and use it directly in your work.
About Prime Checking & Factorization
A prime number is a natural number greater than 1 with no divisors other than 1 and itself (2, 3, 5, 7, 11…). Prime factorization expresses an integer as a product of primes (e.g. 360 = 2³ × 3² × 5). This tool uses trial division and computes instantly in your browser. Your input is never sent to a server.
Features
- Instant prime checkClearly shows whether the entered integer is prime with a badge.
- Factorization viewDisplays the result in exponent notation (2³ × 3² × 5).
- Handles large numbersBigInt arithmetic lets you work with large integers.
- Privacy protectedAll calculations run in your browser; numbers are never uploaded.
Use Cases
- Math homework and verification
- Preparation for finding divisors and GCD
- Checking primes for cryptography or coding study
- Reducing and adding fractions
- Exploring the properties of numbers
FAQ
Are 1 and 0 prime numbers?
No. A prime is a natural number greater than 1 whose only divisors are 1 and itself. 1 is neither prime nor composite, and 0 or negative numbers are not included in the definition.
What is exponent notation in factorization?
When the same prime factor appears multiple times, it is grouped as a power. For example, 360 = 2 × 2 × 2 × 3 × 3 × 5 is written as 360 = 2³ × 3² × 5.
How large a number can it check?
It uses BigInt so it can handle integers with many digits, but because it relies on trial division, very large primes may take a long time. In that case the check stops and shows a message.
What algorithm does it use?
Trial division. After dividing out all factors of 2, it tests odd numbers from 3 up to the square root, extracting prime factors. It is simple and gives exact results.
Is my input saved anywhere?
No. All calculations happen entirely within your browser, and the numbers you enter are never sent to or stored on any server. You can use it with peace of mind.
Feedback
Missing a feature, or getting a result that looks wrong? Let us know — we improve our tools based on your feedback.