The number 12831
12831 is a composite number with 16 divisors. Its prime factorisation is 3 × 7 × 13 × 47. Divisors (16): 1, 3, 7, 13, 21, 39, 47, 91, 141, 273, 329, 611, 987, 1833, 4277, 12831.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 12831: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
12831 is composite. Its prime factorisation is
- 3
The divisors add up to 21504; without 12831 itself that is 8673, so 12831 is deficient (8673 is less than 12831). Euler's totient φ(12831) = 6624 numbers up to 12831 share no factor with it.
- 4
The digits of 12831 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 76 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12831 = 3 \times 7 \times 13 \times 47 \]
12831 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 21504 |
| Euler totient φ(n) | 6624 |
| Square | 164634561 |
| Cube | 2112426052191 |
| Square root | 113.274004 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 76 |
| Scientific notation | 1.2831 × |
12831 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand eight hundred and thirty-one |
| Binary (base 2) | 11001000011111 |
| Octal (base 8) | 31037 |
| Hexadecimal (base 16) | 321F |
| Base 3 | 122121020 |
| As time | 12831 seconds = 3 h 33 min 51 s |
Is 12831 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 | Yes (12831 ÷ 3 = 4277) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (12831 ÷ 7 = 1833) | 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 6) | 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 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 12831 a prime number?
No. 12831 = 3 × 7 × 13 × 47, so it is divisible by 3.
What are the factors of 12831?
1, 3, 7, 13, 21, 39, 47, 91, 141, 273, 329, 611, 987, 1833, 4277, 12831.
What is 12831 in binary?
11001000011111 (hexadecimal 321F, octal 31037).
What is the square root of 12831?
About 113.2740.
Is 12831 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 12831?
12831 is a happy number: repeatedly adding the squares of its digits reaches 1.