The number 81072
81072 is a composite number with 30 divisors. Its prime factorisation is × × 563. Divisors (30): 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144, 563 … 81072.
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How to work it out
- 1
What is special about 81072: a Harshad number: divisible by its digit sum 18.
- 2
81072 is composite. Its prime factorisation is
- 3
The divisors add up to 227292; without 81072 itself that is 146220, so 81072 is abundant (146220 is more than 81072). Euler's totient φ(81072) = 26976 numbers up to 81072 share no factor with it.
- 4
The digits of 81072 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
\[ 81072 = 2^{4} \times 3^{2} \times 563 \]81072 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 30 |
| Sum of divisors | 227292 |
| Euler totient φ(n) | 26976 |
| Square | 6572669184 |
| Cube | 532859436085248 |
| Square root | 284.731452 (= 12√563) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 37 |
| Scientific notation | 8.1072 × |
81072 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand and seventy-two |
| Binary (base 2) | 10011110010110000 |
| Octal (base 8) | 236260 |
| Hexadecimal (base 16) | 13CB0 |
| Base 3 | 11010012200 |
| As time | 81072 seconds = 22 h 31 min 12 s |
Is 81072 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81072 ÷ 2 = 40536) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81072 ÷ 3 = 27024) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (81072 ÷ 4 = 20268) | 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 | Yes (81072 ÷ 6 = 13512) | 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 | Yes (81072 ÷ 8 = 10134) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (81072 ÷ 9 = 9008) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (81072 ÷ 12 = 6756) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81072 a prime number?
No. 81072 = × × 563, so it is divisible by 2.
What are the factors of 81072?
1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72, 144, 563, 1126, 1689, 2252, 3378, 4504, 5067, 6756, 9008, 10134, 13512, 20268, 27024, 40536, 81072.
What is 81072 in binary?
10011110010110000 (hexadecimal 13CB0, octal 236260).
What is the square root of 81072?
About 284.7315, exactly 12√563.
Is 81072 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 81072?
81072 is a Harshad number: divisible by its digit sum 18.