The number 13831
13831 is a palindromic prime: it reads the same backwards and is prime, a twin prime (13829 and 13831 are both prime) and the 1635th prime number. Its only divisors are 1 and 13831.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 13831: a palindromic prime: it reads the same backwards and is prime; a twin prime (13829 and 13831 are both prime); the 1635th prime number; a palindrome: it reads 13831 backwards too.
- 2
13831 is prime, so its only factors are 1 and 13831. It is the 1635th prime; the next prime is 13841 and the one before is 13829.
- 3
The divisors add up to 13832; without 13831 itself that is 1, so 13831 is deficient (1 is less than 13831). Euler's totient φ(13831) = 13830 numbers up to 13831 share no factor with it.
- 4
The digits of 13831 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 89 steps to reach 1.
13831 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 13832 |
| Euler totient φ(n) | 13830 |
| Square | 191296561 |
| Cube | 2645822735191 |
| Square root | 117.605272 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 89 |
| Scientific notation | 1.3831 × |
13831 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand eight hundred and thirty-one |
| Binary (base 2) | 11011000000111 |
| Octal (base 8) | 33007 |
| Hexadecimal (base 16) | 3607 |
| Base 3 | 200222021 |
| As time | 13831 seconds = 3 h 50 min 31 s |
Is 13831 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 1) | 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 1) | 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 7) | 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 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 13831 a prime number?
Yes. 13831 is divisible only by 1 and itself.
What are the factors of 13831?
1, 13831.
What is 13831 in binary?
11011000000111 (hexadecimal 3607, octal 33007).
What is the square root of 13831?
About 117.6053.
Is 13831 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 13831?
13831 is a palindromic prime: it reads the same backwards and is prime; a twin prime (13829 and 13831 are both prime); the 1635th prime number; a palindrome: it reads 13831 backwards too.