Is 1989 a prime number?
No, 1989 is not a prime number. It is divisible by 3: 1989 = 3 × 663.
Is 1989 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 √1989 ≈ 44.60. If none of them divides 1989, it is prime.
- 3
3 divides 1989 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 1989 = 3^{2} \times 13 \times 17 \]Testing 1989 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 1989 ÷ 2 | leaves 1 |
| 3 | 1989 ÷ 3 | divides exactly (663) |
| 5 | 1989 ÷ 5 | leaves 4 |
| 7 | 1989 ÷ 7 | leaves 1 |
| 11 | 1989 ÷ 11 | leaves 9 |
| 13 | 1989 ÷ 13 | divides exactly (153) |
| 17 | 1989 ÷ 17 | divides exactly (117) |
| 19 | 1989 ÷ 19 | leaves 13 |
| 23 | 1989 ÷ 23 | leaves 11 |
| 29 | 1989 ÷ 29 | leaves 17 |
| 31 | 1989 ÷ 31 | leaves 5 |
| 37 | 1989 ÷ 37 | leaves 28 |
Questions
Is 1989 a prime number?
No, 1989 is not a prime number. It is divisible by 3: 1989 = 3 × 663.
What is the next prime after 1989?
1993.
What is the prime number before 1989?
1987.
What are the factors of 1989?
1, 3, 9, 13, 17, 39, 51, 117, 153, 221, 663, 1989.