Factors of 19
Every whole number that divides 19 exactly, the factor pairs, and how to find them yourself.
The answer
The factors of 19 are 1 and 19. 19 is a prime number.
Factor pairs of 19
| Pair | Makes |
|---|---|
| 1 × 19 | 19 |
Prime factors of 19
- Prime factorisation
- 19 = 19
- Is 19 prime?
- Yes. It is the 8th prime number.
- Is 19 a square number?
- No. 4 × 4 = 16 and 5 × 5 = 25, so 19 falls between two square numbers.
How to find the factors of 19
19 is prime, so the only pair you will find is 1 × 19. Work up from 1 to 4, and write down both numbers in every pair you find.
- 19 ÷ 1 = 19, so 1 × 19 is a pair.
- 2 does not go into 19 exactly.
- 3 does not go into 19 exactly.
- 4 does not go into 19 exactly.
Stop at 5: 5 × 5 = 25, which is more than 19. The next pair you would find is 19 × 1, which is 1 × 19 turned round, so you already have every pair.
More numbers
Check whether 19 is prime.
Questions parents ask
What is the largest factor of 19, apart from 19 itself?
1. 19 is prime, so apart from 19 itself its only factor is 1.
What do the factors of 19 add up to?
20. Leaving out 19 itself, they add up to 1, which is less than 19, so 19 is called a deficient number.
Which number after 19 has the same number of factors?
23. Like 19, it has exactly 2 factors.
Number facts are the base of 11+ maths
Factors, multiples, primes and square numbers come up all over 11+ maths, from simplifying fractions to ratio. The free diagnostic checks maths, English and both kinds of reasoning, and shows what to practise next. No card is required.