Factors of 9
Every whole number that divides 9 exactly, the factor pairs, and how to find them yourself.
The answer
The factors of 9 are 1, 3 and 9.
Factor pairs of 9
| Pair | Makes |
|---|---|
| 1 × 9 | 9 |
| 3 × 3 | 9 |
3 × 3 uses the same number twice, so 3 counts once. That is why 9 has an odd number of factors: 3.
Prime factors of 9
- Prime factorisation
- 9 = 3 × 3 (3²)
- Reading index form
- A small raised number tells you how many times to use that factor. For example, 2³ means 2 × 2 × 2.
- Is 9 prime?
- No. It has 3 factors, not just 1 and 9.
- Is 9 a square number?
- Yes. 3 × 3 = 9.
How to find the factors of 9
9 is odd, so every even number you try will fail. It is a square number, so one pair is 3 × 3, the same number twice. Work up from 1 to 3, and write down both numbers in every pair you find.
- 9 ÷ 1 = 9, so 1 × 9 is a pair.
- 2 does not go into 9 exactly.
- 9 ÷ 3 = 3, so 3 × 3 is a pair.
Stop at 4: 4 × 4 = 16, which is more than 9. The next pair you would find is 9 × 1, which is 1 × 9 turned round, so you already have every pair.
9 in the times tables
3 × 3 = 9. Practise the 3 times table.
More numbers
Check whether 9 is prime or see the square root of 9.
Questions parents ask
What is the largest factor of 9, apart from 9 itself?
3. Divide 9 by its smallest factor above 1, which is 3: 9 ÷ 3 = 3.
What do the factors of 9 add up to?
13. Leaving out 9 itself, they add up to 4, which is less than 9, so 9 is called a deficient number.
Which number after 9 has the same number of factors?
25. Like 9, it has exactly 3 factors.
Continue your number practice
Explore the diagnostic for another set of practice questions.