The number 81837
81837 is a composite number with 16 divisors. Its prime factorisation is × 7 × 433. Divisors (16): 1, 3, 7, 9, 21, 27, 63, 189, 433, 1299, 3031, 3897, 9093, 11691, 27279, 81837.
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How to work it out
- 1
What is special about 81837: a Harshad number: divisible by its digit sum 27.
- 2
81837 is composite. Its prime factorisation is
- 3
The divisors add up to 138880; without 81837 itself that is 57043, so 81837 is deficient (57043 is less than 81837). Euler's totient φ(81837) = 46656 numbers up to 81837 share no factor with it.
- 4
The digits of 81837 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 76 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81837 = 3^{3} \times 7 \times 433 \]81837 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 138880 |
| Euler totient φ(n) | 46656 |
| Square | 6697294569 |
| Cube | 548086495643253 |
| Square root | 286.071669 (= 3√9093) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 76 |
| Scientific notation | 8.1837 × |
81837 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand eight hundred and thirty-seven |
| Binary (base 2) | 10011111110101101 |
| Octal (base 8) | 237655 |
| Hexadecimal (base 16) | 13FAD |
| Base 3 | 11011021000 |
| As time | 81837 seconds = 22 h 43 min 57 s |
Is 81837 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 (81837 ÷ 3 = 27279) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | 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 (81837 ÷ 7 = 11691) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (81837 ÷ 9 = 9093) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81837 a prime number?
No. 81837 = × 7 × 433, so it is divisible by 3.
What are the factors of 81837?
1, 3, 7, 9, 21, 27, 63, 189, 433, 1299, 3031, 3897, 9093, 11691, 27279, 81837.
What is 81837 in binary?
10011111110101101 (hexadecimal 13FAD, octal 237655).
What is the square root of 81837?
About 286.0717, exactly 3√9093.
Is 81837 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 81837?
81837 is a Harshad number: divisible by its digit sum 27.