Is 428 a prime number?
No, 428 is not a prime number. It is divisible by 2: 428 = 2 × 214.
Is 428 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 √428 ≈ 20.69. If none of them divides 428, it is prime.
- 3
2 divides 428 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 428 = 2^{2} \times 107 \]Testing 428 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 428 ÷ 2 | divides exactly (214) |
| 3 | 428 ÷ 3 | leaves 2 |
| 5 | 428 ÷ 5 | leaves 3 |
| 7 | 428 ÷ 7 | leaves 1 |
| 11 | 428 ÷ 11 | leaves 10 |
| 13 | 428 ÷ 13 | leaves 12 |
| 17 | 428 ÷ 17 | leaves 3 |
| 19 | 428 ÷ 19 | leaves 10 |
Questions
Is 428 a prime number?
No, 428 is not a prime number. It is divisible by 2: 428 = 2 × 214.
What is the next prime after 428?
431.
What is the prime number before 428?
421.
What are the factors of 428?
1, 2, 4, 107, 214, 428.