Is 53 a prime number?
53 is a prime number. Here is how to check it, one division at a time.
The answer
Yes. 53 is a prime number: its only factors are 1 and 53.
How to check that 53 is prime
Try dividing 53 by the prime numbers, starting with 2. You only need primes: if 4 went into 53, then 2 would too.
- 53 ÷ 2 = 26 remainder 1, so 2 is not a factor.
- 53 ÷ 3 = 17 remainder 2, so 3 is not a factor.
- 53 ÷ 5 = 10 remainder 3, so 5 is not a factor.
- 53 ÷ 7 = 7 remainder 4, so 7 is not a factor.
Stop at 11: 11 × 11 = 121, which is more than 53. Any factor bigger than that would need a partner smaller than 11, and you have already tried those. So 53 is prime.
Where 53 comes among the primes
53 is the 16th prime number. The prime just before it is 47.
There are 25 prime numbers up to 100: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89 and 97.
Around 53
- 53 is not in any times table from 2 to 12. The answers either side of it are 50 (5 × 10 and 10 × 5) and 54 (6 × 9 and 9 × 6).
- The nearest square number is 49 (7 × 7), 4 below it.
53 at a glance
Optional extra number facts:
- In words
- fifty-three
- In Roman numerals
- LIII
- Odd or even
- Odd: it ends in 3
- Its factors add up to
- 54, or 1 without 53 itself. 53 is deficient: Deficient means this sum is less than the number.
Related pages
More numbers
Questions parents ask
Is 53 one of a pair of twin primes?
No. Twin primes are two primes 2 apart, such as 11 and 13. Neither 51 nor 55 is prime, so 53 has no twin.
What is the next prime number after 53?
59, which is 6 more than 53. Every number in between has a factor other than 1 and itself.
What is 53 × 53?
53 × 53 = 2809. The square of a prime has exactly three factors: 1, 53 and 2809.
Continue your number practice
Explore the diagnostic for another set of practice questions.