Factor Calculator
Find all factors and factor pairs of any positive integer. Determine if a number is prime and see the total count of divisors instantly.
What is a Factor?
A factor (or divisor) is a whole number that divides another number evenly, leaving no remainder.
For example, the factors of 12 are: 1, 2, 3, 4, 6, 12.
Because:
1 × 12 = 12
2 × 6 = 12
3 × 4 = 12
Factor Pairs
Factor pairs are two numbers that multiply together to give the original number. Every number has at least one factor pair: 1 and itself.
Prime vs Composite Numbers
- Prime Number: A number that has exactly two factors: 1 and itself (e.g., 2, 3, 5, 7, 11).
- Composite Number: A number that has more than two factors (e.g., 4, 6, 8, 9, 10).
- Square Number: A number that has an odd number of factors (e.g., 9 has 1, 3, 9). This happens because one of the factor pairs is the same number repeated (3 × 3).
? Frequently Asked Questions
Start dividing the number by 1, 2, 3, etc. If the division results in a whole number, that divisor is a factor. Stop when you reach the square root of the number.
Yes. 1 is a factor of every integer because any number divided by 1 equals itself.
Yes, factors can be negative. For example, -2 and -3 are factors of 6 because -2 × -3 = 6. However, this calculator focuses on positive factors for simplicity.