Factors of 25
Every whole number that divides 25 exactly, the factor pairs, and how to find them yourself.
The answer
The factors of 25 are 1, 5 and 25.
Factor pairs of 25
| Pair | Makes |
|---|---|
| 1 × 25 | 25 |
| 5 × 5 | 25 |
5 × 5 uses the same number twice, so 5 counts once. That is why 25 has an odd number of factors: 3.
Prime factors of 25
- Prime factorisation
- 25 = 5 × 5 (5²)
- Reading index form
- A small raised number tells you how many times to use that factor. For example, 2³ means 2 × 2 × 2.
- Is 25 prime?
- No. It has 3 factors, not just 1 and 25.
- Is 25 a square number?
- Yes. 5 × 5 = 25.
How to find the factors of 25
25 is odd, so every even number you try will fail. It ends in 5, so 5 is a factor. It is a square number, so one pair is 5 × 5, the same number twice. Work up from 1 to 5, and write down both numbers in every pair you find.
- 25 ÷ 1 = 25, so 1 × 25 is a pair.
- 2 does not go into 25 exactly.
- 3 does not go into 25 exactly.
- 4 does not go into 25 exactly.
- 25 ÷ 5 = 5, so 5 × 5 is a pair.
Stop at 6: 6 × 6 = 36, which is more than 25. The next pair you would find is 25 × 1, which is 1 × 25 turned round, so you already have every pair.
25 in the times tables
5 × 5 = 25. Practise the 5 times table.
More numbers
Check whether 25 is prime or see the square root of 25.
Questions parents ask
What is the largest factor of 25, apart from 25 itself?
5. Divide 25 by its smallest factor above 1, which is 5: 25 ÷ 5 = 5.
What do the factors of 25 add up to?
31. Leaving out 25 itself, they add up to 6, which is less than 25, so 25 is called a deficient number.
Which number after 25 has the same number of factors?
49. Like 25, it has exactly 3 factors.
Continue your number practice
Explore the diagnostic for another set of practice questions.