The number 83781
83781 is a composite number with 16 divisors. Its prime factorisation is × 29 × 107. Divisors (16): 1, 3, 9, 27, 29, 87, 107, 261, 321, 783, 963, 2889, 3103, 9309, 27927, 83781.
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How to work it out
- 1
What is special about 83781: a Harshad number: divisible by its digit sum 27.
- 2
83781 is composite. Its prime factorisation is
- 3
The divisors add up to 129600; without 83781 itself that is 45819, so 83781 is deficient (45819 is less than 83781). Euler's totient φ(83781) = 53424 numbers up to 83781 share no factor with it.
- 4
The digits of 83781 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 89 steps to reach 1.
LaTeX source of the formulas on this page
\[ 83781 = 3^{3} \times 29 \times 107 \]83781 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 129600 |
| Euler totient φ(n) | 53424 |
| Square | 7019255961 |
| Cube | 588080283668541 |
| Square root | 289.449477 (= 3√9309) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 89 |
| Scientific notation | 8.3781 × |
83781 in other forms
| Form | Value |
|---|---|
| In words | eighty-three thousand seven hundred and eighty-one |
| Binary (base 2) | 10100011101000101 |
| Octal (base 8) | 243505 |
| Hexadecimal (base 16) | 14745 |
| Base 3 | 11020221000 |
| As time | 83781 seconds = 23 h 16 min 21 s |
Is 83781 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 (83781 ÷ 3 = 27927) | 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 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 | No (remainder 5) | 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 (83781 ÷ 9 = 9309) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 83781 a prime number?
No. 83781 = × 29 × 107, so it is divisible by 3.
What are the factors of 83781?
1, 3, 9, 27, 29, 87, 107, 261, 321, 783, 963, 2889, 3103, 9309, 27927, 83781.
What is 83781 in binary?
10100011101000101 (hexadecimal 14745, octal 243505).
What is the square root of 83781?
About 289.4495, exactly 3√9309.
Is 83781 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 83781?
83781 is a Harshad number: divisible by its digit sum 27.