Is 8421 a prime number?
No, 8421 is not a prime number. It is divisible by 3: 8421 = 3 × 2807.
Is 8421 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 √8421 ≈ 91.77. If none of them divides 8421, it is prime.
- 3
3 divides 8421 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 8421 = 3 \times 7 \times 401 \]
Testing 8421 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 8421 ÷ 2 | leaves 1 |
| 3 | 8421 ÷ 3 | divides exactly (2807) |
| 5 | 8421 ÷ 5 | leaves 1 |
| 7 | 8421 ÷ 7 | divides exactly (1203) |
| 11 | 8421 ÷ 11 | leaves 6 |
| 13 | 8421 ÷ 13 | leaves 10 |
| 17 | 8421 ÷ 17 | leaves 6 |
| 19 | 8421 ÷ 19 | leaves 4 |
| 23 | 8421 ÷ 23 | leaves 3 |
| 29 | 8421 ÷ 29 | leaves 11 |
| 31 | 8421 ÷ 31 | leaves 20 |
| 37 | 8421 ÷ 37 | leaves 22 |
Questions
Is 8421 a prime number?
No, 8421 is not a prime number. It is divisible by 3: 8421 = 3 × 2807.
What is the next prime after 8421?
8423.
What is the prime number before 8421?
8419.
What are the factors of 8421?
1, 3, 7, 21, 401, 1203, 2807, 8421.