The number 18311
18311 is a twin prime (18311 and 18313 are both prime) and the 2099th prime number. Its only divisors are 1 and 18311.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18311: a twin prime (18311 and 18313 are both prime); the 2099th prime number.
- 2
18311 is prime, so its only factors are 1 and 18311. It is the 2099th prime; the next prime is 18313 and the one before is 18307.
- 3
The divisors add up to 18312; without 18311 itself that is 1, so 18311 is deficient (1 is less than 18311). Euler's totient φ(18311) = 18310 numbers up to 18311 share no factor with it.
- 4
The digits of 18311 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 154 steps to reach 1.
18311 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 18312 |
| Euler totient φ(n) | 18310 |
| Square | 335292721 |
| Cube | 6139545014231 |
| Square root | 135.318144 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 154 |
| Scientific notation | 1.8311 × |
18311 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand three hundred and eleven |
| Binary (base 2) | 100011110000111 |
| Octal (base 8) | 43607 |
| Hexadecimal (base 16) | 4787 |
| Base 3 | 221010012 |
| As time | 18311 seconds = 5 h 5 min 11 s |
Is 18311 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18311 a prime number?
Yes. 18311 is divisible only by 1 and itself.
What are the factors of 18311?
1, 18311.
What is 18311 in binary?
100011110000111 (hexadecimal 4787, octal 43607).
What is the square root of 18311?
About 135.3181.
Is 18311 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 18311?
18311 is a twin prime (18311 and 18313 are both prime); the 2099th prime number.