Is 2005 a prime number?
No, 2005 is not a prime number. It is divisible by 5: 2005 = 5 × 401.
Is 2005 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 √2005 ≈ 44.78. If none of them divides 2005, it is prime.
- 3
5 divides 2005 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 2005 = 5 \times 401 \]
Testing 2005 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 2005 ÷ 2 | leaves 1 |
| 3 | 2005 ÷ 3 | leaves 1 |
| 5 | 2005 ÷ 5 | divides exactly (401) |
| 7 | 2005 ÷ 7 | leaves 3 |
| 11 | 2005 ÷ 11 | leaves 3 |
| 13 | 2005 ÷ 13 | leaves 3 |
| 17 | 2005 ÷ 17 | leaves 16 |
| 19 | 2005 ÷ 19 | leaves 10 |
| 23 | 2005 ÷ 23 | leaves 4 |
| 29 | 2005 ÷ 29 | leaves 4 |
| 31 | 2005 ÷ 31 | leaves 21 |
| 37 | 2005 ÷ 37 | leaves 7 |
Questions
Is 2005 a prime number?
No, 2005 is not a prime number. It is divisible by 5: 2005 = 5 × 401.
What is the next prime after 2005?
2011.
What is the prime number before 2005?
2003.
What are the factors of 2005?
1, 5, 401, 2005.