The number 81360
81360 is a composite number with 60 divisors. Its prime factorisation is × × 5 × 113. Divisors (60): 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30 … 81360.
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How to work it out
- 1
What is special about 81360: a Harshad number: divisible by its digit sum 18.
- 2
81360 is composite. Its prime factorisation is
- 3
The divisors add up to 275652; without 81360 itself that is 194292, so 81360 is abundant (194292 is more than 81360). Euler's totient φ(81360) = 21504 numbers up to 81360 share no factor with it.
- 4
The digits of 81360 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 37 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81360 = 2^{4} \times 3^{2} \times 5 \times 113 \]81360 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 60 |
| Sum of divisors | 275652 |
| Euler totient φ(n) | 21504 |
| Square | 6619449600 |
| Cube | 538558419456000 |
| Square root | 285.236744 (= 12√565) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 37 |
| Scientific notation | 8.136 × |
81360 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand three hundred and sixty |
| Binary (base 2) | 10011110111010000 |
| Octal (base 8) | 236720 |
| Hexadecimal (base 16) | 13DD0 |
| Base 3 | 11010121100 |
| As time | 81360 seconds = 22 h 36 min 0 s |
Is 81360 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81360 ÷ 2 = 40680) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81360 ÷ 3 = 27120) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (81360 ÷ 4 = 20340) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (81360 ÷ 5 = 16272) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (81360 ÷ 6 = 13560) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 (81360 ÷ 8 = 10170) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (81360 ÷ 9 = 9040) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (81360 ÷ 10 = 8136) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (81360 ÷ 12 = 6780) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81360 a prime number?
No. 81360 = × × 5 × 113, so it is divisible by 2.
What are the factors of 81360?
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 16, 18, 20, 24, 30, 36, 40, 45, 48, 60, 72, 80, 90, 113, 120, 144, 180, 226, 240, 339, 360, 452, 565, 678, 720, 904, 1017, 1130, 1356, 1695, 1808, 2034, 2260, 2712, 3390, 4068, 4520, 5085, 5424, 6780, 8136, 9040, 10170, 13560, 16272, 20340, 27120, 40680, 81360.
What is 81360 in binary?
10011110111010000 (hexadecimal 13DD0, octal 236720).
What is the square root of 81360?
About 285.2367, exactly 12√565.
Is 81360 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 81360?
81360 is a Harshad number: divisible by its digit sum 18.