Is 1155 a prime number?
No, 1155 is not a prime number. It is divisible by 3: 1155 = 3 × 385.
Is 1155 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 √1155 ≈ 33.99. If none of them divides 1155, it is prime.
- 3
3 divides 1155 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 1155 = 3 \times 5 \times 7 \times 11 \]
Testing 1155 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 1155 ÷ 2 | leaves 1 |
| 3 | 1155 ÷ 3 | divides exactly (385) |
| 5 | 1155 ÷ 5 | divides exactly (231) |
| 7 | 1155 ÷ 7 | divides exactly (165) |
| 11 | 1155 ÷ 11 | divides exactly (105) |
| 13 | 1155 ÷ 13 | leaves 11 |
| 17 | 1155 ÷ 17 | leaves 16 |
| 19 | 1155 ÷ 19 | leaves 15 |
| 23 | 1155 ÷ 23 | leaves 5 |
| 29 | 1155 ÷ 29 | leaves 24 |
| 31 | 1155 ÷ 31 | leaves 8 |
Questions
Is 1155 a prime number?
No, 1155 is not a prime number. It is divisible by 3: 1155 = 3 × 385.
What is the next prime after 1155?
1163.
What is the prime number before 1155?
1153.
What are the factors of 1155?
1, 3, 5, 7, 11, 15, 21, 33, 35, 55, 77, 105, 165, 231, 385, 1155.