The number 18081
18081 is a palindrome: it reads 18081 backwards too. Its prime factorisation is × × 41. Divisors (18): 1, 3, 7, 9, 21, 41, 49, 63, 123, 147, 287, 369, 441, 861, 2009, 2583 … 18081.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18081: a palindrome: it reads 18081 backwards too; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18081 is composite. Its prime factorisation is
- 3
The divisors add up to 31122; without 18081 itself that is 13041, so 18081 is deficient (13041 is less than 18081). Euler's totient φ(18081) = 10080 numbers up to 18081 share no factor with it.
- 4
The digits of 18081 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 92 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18081 = 3^{2} \times 7^{2} \times 41 \]18081 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 18 |
| Sum of divisors | 31122 |
| Euler totient φ(n) | 10080 |
| Square | 326922561 |
| Cube | 5911086825441 |
| Square root | 134.465609 (= 21√41) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 92 |
| Scientific notation | 1.8081 × |
18081 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand and eighty-one |
| Binary (base 2) | 100011010100001 |
| Octal (base 8) | 43241 |
| Hexadecimal (base 16) | 46A1 |
| Base 3 | 220210200 |
| As time | 18081 seconds = 5 h 1 min 21 s |
Is 18081 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 (18081 ÷ 3 = 6027) | 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 | Yes (18081 ÷ 7 = 2583) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (18081 ÷ 9 = 2009) | 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 8) | 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 18081 a prime number?
No. 18081 = × × 41, so it is divisible by 3.
What are the factors of 18081?
1, 3, 7, 9, 21, 41, 49, 63, 123, 147, 287, 369, 441, 861, 2009, 2583, 6027, 18081.
What is 18081 in binary?
100011010100001 (hexadecimal 46A1, octal 43241).
What is the square root of 18081?
About 134.4656, exactly 21√41.
Is 18081 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 18081?
18081 is a palindrome: it reads 18081 backwards too; a happy number: repeatedly adding the squares of its digits reaches 1.