Quick start
- Enter one positive whole number.
- Press Factor into primes.
- Read the prime factorization in the result card.
- Use the steps to check repeated factors, prime powers, and recent answers.
Best uses
These are the situations this tool is meant for. If your task is close to one of these, the examples and notes below can help you choose the right inputs.
- Rewrite a number as prime factors for homework or study notes.
- Check whether a number is prime or composite.
- Compare prime factorization with factors, GCF, and LCM work.
- Break down numbers before simplifying fractions or ratios.
What the answer means
Prime factorization is a clean way to break a number into building blocks. Prime numbers cannot be broken into smaller whole-number factors other than 1 and themselves.
For example, 360 becomes 2^3 x 3^2 x 5. That means 2 x 2 x 2 x 3 x 3 x 5. Multiplying those factors returns 360.
When to use it
Prime factorization helps when you are simplifying fractions, finding GCF or LCM, checking divisibility, or studying how numbers are built.
If you need every factor pair instead, use the Factor Calculator. If you only need the largest shared factor across several numbers, use the Greatest Common Factor Calculator.
Examples from the calculator
2^3 x 3^2 x 5
9973 is prime
2^4 x 3^2 x 5 x 7
FAQ in plain language
What does prime factorization mean?
Prime factorization rewrites a whole number as prime numbers multiplied together. For example, 360 becomes 2^3 x 3^2 x 5.
What is a prime number?
A prime number is a whole number greater than 1 with exactly two positive factors: 1 and itself.
Why do repeated prime factors become exponents?
Exponents keep repeated factors short. Instead of writing 2 x 2 x 2, the calculator writes 2^3.
Related tools
- Factor Calculator List factors, factor pairs, and prime factorization for a whole number.
- Greatest Common Factor Calculator Find the greatest common factor of two or more whole numbers with steps.
- Least Common Multiple Calculator Find the least common multiple of two or more whole numbers with steps.
Privacy and copying results
Recent answers stay visible only while you work in the current browser tab. They are not sent to a server.
Use Copy answer when you want to paste the expression and result into notes, homework, a message, or another document. Check the units and assumptions before copying.