The number 18165
18165 is a composite number with 16 divisors. Its prime factorisation is 3 × 5 × 7 × 173. Divisors (16): 1, 3, 5, 7, 15, 21, 35, 105, 173, 519, 865, 1211, 2595, 3633, 6055, 18165.
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How to work it out
- 1
What is special about 18165: a Harshad number: divisible by its digit sum 21.
- 2
18165 is composite. Its prime factorisation is
- 3
The divisors add up to 33408; without 18165 itself that is 15243, so 18165 is deficient (15243 is less than 18165). Euler's totient φ(18165) = 8256 numbers up to 18165 share no factor with it.
- 4
The digits of 18165 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 66 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18165 = 3 \times 5 \times 7 \times 173 \]
18165 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 33408 |
| Euler totient φ(n) | 8256 |
| Square | 329967225 |
| Cube | 5993854642125 |
| Square root | 134.777595 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 66 |
| Scientific notation | 1.8165 × |
18165 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand one hundred and sixty-five |
| Binary (base 2) | 100011011110101 |
| Octal (base 8) | 43365 |
| Hexadecimal (base 16) | 46F5 |
| Base 3 | 220220210 |
| As time | 18165 seconds = 5 h 2 min 45 s |
Is 18165 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 (18165 ÷ 3 = 6055) | 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 | Yes (18165 ÷ 5 = 3633) | 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 (18165 ÷ 7 = 2595) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | 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 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18165 a prime number?
No. 18165 = 3 × 5 × 7 × 173, so it is divisible by 3.
What are the factors of 18165?
1, 3, 5, 7, 15, 21, 35, 105, 173, 519, 865, 1211, 2595, 3633, 6055, 18165.
What is 18165 in binary?
100011011110101 (hexadecimal 46F5, octal 43365).
What is the square root of 18165?
About 134.7776.
Is 18165 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 18165?
18165 is a Harshad number: divisible by its digit sum 21.