Is 77 a prime number?
No, 77 is not a prime number. It is divisible by 7: 77 = 7 × 11.
Is 77 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 √77 ≈ 8.77. If none of them divides 77, it is prime.
- 3
7 divides 77 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 77 = 7 \times 11 \]
Testing 77 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 77 ÷ 2 | leaves 1 |
| 3 | 77 ÷ 3 | leaves 2 |
| 5 | 77 ÷ 5 | leaves 2 |
| 7 | 77 ÷ 7 | divides exactly (11) |
Questions
Is 77 a prime number?
No, 77 is not a prime number. It is divisible by 7: 77 = 7 × 11.
What is the next prime after 77?
79.
What is the prime number before 77?
73.
What are the factors of 77?
1, 7, 11, 77.