What is the 125th prime number?
The 125th prime number is 691. The next prime is 701 (a gap of 10) and the one before is 683.
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 125th one is 691.
- 2
691 is prime because no prime up to ā691 ā 26.29 divides it.
- 3
The primes are spread thinner as numbers grow: by the prime number theorem the 125th prime is close to 125 Ć ln(125) ā 604, and here it is 691.
- 4
691 has no twin: neither 689 nor 693 is prime.
Primes around the 125th
| Position | Prime | Gap from the previous |
|---|---|---|
| 122 | 673 | 12 |
| 123 | 677 | 4 |
| 124 | 683 | 6 |
| 125 | 691 | 8 |
| 126 | 701 | 10 |
| 127 | 709 | 8 |
| 128 | 719 | 10 |
Questions
What is the 125th prime number?
691.
Which prime number is 691?
691 is the 125th prime number.
What is the sum of the first 125 primes?
39,612.