What is the 80th prime number?
The 80th prime number is 409. The next prime is 419 (a gap of 10) and the one before is 401.
Position
Pick any whole number from 1 to 10,000.
How to work it out
- 1
List the primes in order: 2, 3, 5, 7, 11, 13, ā¦ The 80th one is 409.
- 2
409 is prime because no prime up to ā409 ā 20.22 divides it.
- 3
The primes are spread thinner as numbers grow: by the prime number theorem the 80th prime is close to 80 Ć ln(80) ā 351, and here it is 409.
- 4
409 has no twin: neither 407 nor 411 is prime.
Primes around the 80th
| Position | Prime | Gap from the previous |
|---|---|---|
| 77 | 389 | 6 |
| 78 | 397 | 8 |
| 79 | 401 | 4 |
| 80 | 409 | 8 |
| 81 | 419 | 10 |
| 82 | 421 | 2 |
| 83 | 431 | 10 |
Questions
What is the 80th prime number?
409.
Which prime number is 409?
409 is the 80th prime number.
What is the sum of the first 80 primes?
14,697.