The number 18161
18161 is a composite number with 8 divisors. Its prime factorisation is 11 × 13 × 127. Divisors (8): 1, 11, 13, 127, 143, 1397, 1651, 18161.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18161: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18161 is composite. Its prime factorisation is
- 3
The divisors add up to 21504; without 18161 itself that is 3343, so 18161 is deficient (3343 is less than 18161). Euler's totient φ(18161) = 15120 numbers up to 18161 share no factor with it.
- 4
The digits of 18161 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 66 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18161 = 11 \times 13 \times 127 \]
18161 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 21504 |
| Euler totient φ(n) | 15120 |
| Square | 329821921 |
| Cube | 5989895907281 |
| Square root | 134.762754 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 66 |
| Scientific notation | 1.8161 × |
18161 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand one hundred and sixty-one |
| Binary (base 2) | 100011011110001 |
| Octal (base 8) | 43361 |
| Hexadecimal (base 16) | 46F1 |
| Base 3 | 220220122 |
| As time | 18161 seconds = 5 h 2 min 41 s |
Is 18161 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 | No (remainder 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 | No (remainder 8) | 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 | Yes (18161 ÷ 11 = 1651) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18161 a prime number?
No. 18161 = 11 × 13 × 127, so it is divisible by 11.
What are the factors of 18161?
1, 11, 13, 127, 143, 1397, 1651, 18161.
What is 18161 in binary?
100011011110001 (hexadecimal 46F1, octal 43361).
What is the square root of 18161?
About 134.7628.
Is 18161 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 18161?
18161 is a happy number: repeatedly adding the squares of its digits reaches 1.