Is 78 a prime number?
No, 78 is not a prime number. It is divisible by 2: 78 = 2 × 39.
Is 78 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 √78 ≈ 8.83. If none of them divides 78, it is prime.
- 3
2 divides 78 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 78 = 2 \times 3 \times 13 \]
Testing 78 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 78 ÷ 2 | divides exactly (39) |
| 3 | 78 ÷ 3 | divides exactly (26) |
| 5 | 78 ÷ 5 | leaves 3 |
| 7 | 78 ÷ 7 | leaves 1 |
Questions
Is 78 a prime number?
No, 78 is not a prime number. It is divisible by 2: 78 = 2 × 39.
What is the next prime after 78?
79.
What is the prime number before 78?
73.
What are the factors of 78?
1, 2, 3, 6, 13, 26, 39, 78.