How to use
- Enter a whole number from 2 to 10^15.
- Read whether it is prime and its prime factorization.
- Check the factor tree and the list of all factors below.
Options explained
- Exponent form
- Repeated primes are written with powers — 2 × 2 × 2 × 3 × 3 × 5 becomes 2³ × 3² × 5. The written-out product is shown as well.
- Number of factors
- Add 1 to each exponent and multiply. 360 = 2³ × 3² × 5¹ has (3 + 1)(2 + 1)(1 + 1) = 24 factors.
Examples
| Number | Prime factorization | Number of factors |
|---|---|---|
| 12 | 2² × 3 | 6 |
| 60 | 2² × 3 × 5 | 12 |
| 360 | 2³ × 3² × 5 | 24 |
| 1001 | 7 × 11 × 13 | 8 |
| 97 | 97 (prime) | 2 |
Frequently asked questions
Is 1 a prime number?
No. A prime has exactly two factors, 1 and itself, and 1 has only one. 2 is the smallest prime and the only even one.
How does the calculator find the factors?
It divides by 2, 3 and then numbers of the form 6k ± 1 up to the square root, which is enough to factor any number up to 10^15 in under a second.
What is a factor tree?
A diagram that splits the number into two factors again and again until only primes are left. The circled numbers at the ends of the branches are the prime factors.
Privacy
This tool runs entirely in your browser. Your files and text are processed on your device and are never uploaded to our servers.