The number 81783
81783 is a composite number with 16 divisors. Its prime factorisation is × 13 × 233. Divisors (16): 1, 3, 9, 13, 27, 39, 117, 233, 351, 699, 2097, 3029, 6291, 9087, 27261, 81783.
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How to work it out
- 1
What is special about 81783: a Harshad number: divisible by its digit sum 27.
- 2
81783 is composite. Its prime factorisation is
- 3
The divisors add up to 131040; without 81783 itself that is 49257, so 81783 is deficient (49257 is less than 81783). Euler's totient φ(81783) = 50112 numbers up to 81783 share no factor with it.
- 4
The digits of 81783 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 63 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81783 = 3^{3} \times 13 \times 233 \]81783 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 131040 |
| Euler totient φ(n) | 50112 |
| Square | 6688459089 |
| Cube | 547002249675687 |
| Square root | 285.977272 (= 3√9087) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 63 |
| Scientific notation | 8.1783 × |
81783 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand seven hundred and eighty-three |
| Binary (base 2) | 10011111101110111 |
| Octal (base 8) | 237567 |
| Hexadecimal (base 16) | 13F77 |
| Base 3 | 11011012000 |
| As time | 81783 seconds = 22 h 43 min 3 s |
Is 81783 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 (81783 ÷ 3 = 27261) | 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 3) | 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 | No (remainder 2) | 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 | Yes (81783 ÷ 9 = 9087) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | 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 81783 a prime number?
No. 81783 = × 13 × 233, so it is divisible by 3.
What are the factors of 81783?
1, 3, 9, 13, 27, 39, 117, 233, 351, 699, 2097, 3029, 6291, 9087, 27261, 81783.
What is 81783 in binary?
10011111101110111 (hexadecimal 13F77, octal 237567).
What is the square root of 81783?
About 285.9773, exactly 3√9087.
Is 81783 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 81783?
81783 is a Harshad number: divisible by its digit sum 27.