Factor Calculator
List all the factors of a number or write it as a product of primes.
Factors and prime factors
A factor of a number divides it exactly with no remainder. The factors of 12 are 1, 2, 3, 4, 6 and 12. A prime factorization writes the number as a product of primes only: 12 = 2² × 3.
Example
360 = 2³ × 3² × 5. Adding one to each power and multiplying, (3 + 1) × (2 + 1) × (1 + 1) = 24, so 360 has 24 factors.
Handy facts
- A prime number has exactly two factors: 1 and itself.
- Factors come in pairs that multiply to the number, so the calculator only needs to search up to its square root.
- 1 is neither prime nor composite.
Frequently asked questions
How large a number can it handle?
Up to 1,000,000,000,000 for factors and 10,000,000,000,000 for prime factorization, which are fast in your browser.
What is a perfect number?
A number equal to the sum of its proper factors, such as 6 (1 + 2 + 3) and 28.
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