The number 81384
81384 is a composite number with 16 divisors. Its prime factorisation is × 3 × 3391. Divisors (16): 1, 2, 3, 4, 6, 8, 12, 24, 3391, 6782, 10173, 13564, 20346, 27128, 40692, 81384.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81384: a Harshad number: divisible by its digit sum 24.
- 2
81384 is composite. Its prime factorisation is
- 3
The divisors add up to 203520; without 81384 itself that is 122136, so 81384 is abundant (122136 is more than 81384). Euler's totient φ(81384) = 27120 numbers up to 81384 share no factor with it.
- 4
The digits of 81384 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 182 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81384 = 2^{3} \times 3 \times 3391 \]81384 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 203520 |
| Euler totient φ(n) | 27120 |
| Square | 6623355456 |
| Cube | 539035160431104 |
| Square root | 285.278811 (= 2√20346) |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 182 |
| Scientific notation | 8.1384 × |
81384 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand three hundred and eighty-four |
| Binary (base 2) | 10011110111101000 |
| Octal (base 8) | 236750 |
| Hexadecimal (base 16) | 13DE8 |
| Base 3 | 11010122020 |
| As time | 81384 seconds = 22 h 36 min 24 s |
Is 81384 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81384 ÷ 2 = 40692) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81384 ÷ 3 = 27128) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (81384 ÷ 4 = 20346) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (81384 ÷ 6 = 13564) | 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 | Yes (81384 ÷ 8 = 10173) | 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 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (81384 ÷ 12 = 6782) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81384 a prime number?
No. 81384 = × 3 × 3391, so it is divisible by 2.
What are the factors of 81384?
1, 2, 3, 4, 6, 8, 12, 24, 3391, 6782, 10173, 13564, 20346, 27128, 40692, 81384.
What is 81384 in binary?
10011110111101000 (hexadecimal 13DE8, octal 236750).
What is the square root of 81384?
About 285.2788, exactly 2√20346.
Is 81384 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 81384?
81384 is a Harshad number: divisible by its digit sum 24.