Is 321 a prime number?
No, 321 is not a prime number. It is divisible by 3: 321 = 3 × 107.
Is 321 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 √321 ≈ 17.92. If none of them divides 321, it is prime.
- 3
3 divides 321 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 321 = 3 \times 107 \]
Testing 321 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 321 ÷ 2 | leaves 1 |
| 3 | 321 ÷ 3 | divides exactly (107) |
| 5 | 321 ÷ 5 | leaves 1 |
| 7 | 321 ÷ 7 | leaves 6 |
| 11 | 321 ÷ 11 | leaves 2 |
| 13 | 321 ÷ 13 | leaves 9 |
| 17 | 321 ÷ 17 | leaves 15 |
Questions
Is 321 a prime number?
No, 321 is not a prime number. It is divisible by 3: 321 = 3 × 107.
What is the next prime after 321?
331.
What is the prime number before 321?
317.
What are the factors of 321?
1, 3, 107, 321.