The number 18009
18009 is a composite number with 16 divisors. Its prime factorisation is × 23 × 29. Divisors (16): 1, 3, 9, 23, 27, 29, 69, 87, 207, 261, 621, 667, 783, 2001, 6003, 18009.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
18009 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
18009 is composite. Its prime factorisation is
- 3
The divisors add up to 28800; without 18009 itself that is 10791, so 18009 is deficient (10791 is less than 18009). Euler's totient φ(18009) = 11088 numbers up to 18009 share no factor with it.
- 4
The digits of 18009 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 79 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18009 = 3^{3} \times 23 \times 29 \]18009 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 28800 |
| Euler totient φ(n) | 11088 |
| Square | 324324081 |
| Cube | 5840752374729 |
| Square root | 134.197615 (= 3√2001) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 79 |
| Scientific notation | 1.8009 × |
18009 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand and nine |
| Binary (base 2) | 100011001011001 |
| Octal (base 8) | 43131 |
| Hexadecimal (base 16) | 4659 |
| Base 3 | 220201000 |
| As time | 18009 seconds = 5 h 0 min 9 s |
Is 18009 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 (18009 ÷ 3 = 6003) | 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 4) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (18009 ÷ 9 = 2001) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | 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 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18009 a prime number?
No. 18009 = × 23 × 29, so it is divisible by 3.
What are the factors of 18009?
1, 3, 9, 23, 27, 29, 69, 87, 207, 261, 621, 667, 783, 2001, 6003, 18009.
What is 18009 in binary?
100011001011001 (hexadecimal 4659, octal 43131).
What is the square root of 18009?
About 134.1976, exactly 3√2001.
Is 18009 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 18009?
It is a composite number with 16 divisors.