Is 55 a prime number?
No, 55 is not a prime number. It is divisible by 5: 55 = 5 × 11.
Is 55 prime?
Pick any whole number from 1 to 10,000.
How to work it out
- 1
A prime number has exactly two factors: 1 and itself.
- 2
It is enough to test the primes up to √55 ≈ 7.42. If none of them divides 55, it is prime.
- 3
5 divides 55 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 55 = 5 \times 11 \]
Testing 55 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 55 ÷ 2 | leaves 1 |
| 3 | 55 ÷ 3 | leaves 1 |
| 5 | 55 ÷ 5 | divides exactly (11) |
| 7 | 55 ÷ 7 | leaves 6 |
Questions
Is 55 a prime number?
No, 55 is not a prime number. It is divisible by 5: 55 = 5 × 11.
What is the next prime after 55?
59.
What is the prime number before 55?
53.
What are the factors of 55?
1, 5, 11, 55.