The number 18321
18321 is a composite number with 8 divisors. Its prime factorisation is 3 × 31 × 197. Divisors (8): 1, 3, 31, 93, 197, 591, 6107, 18321.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18321: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18321 is composite. Its prime factorisation is
- 3
The divisors add up to 25344; without 18321 itself that is 7023, so 18321 is deficient (7023 is less than 18321). Euler's totient φ(18321) = 11760 numbers up to 18321 share no factor with it.
- 4
The digits of 18321 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 154 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18321 = 3 \times 31 \times 197 \]
18321 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 25344 |
| Euler totient φ(n) | 11760 |
| Square | 335659041 |
| Cube | 6149609290161 |
| Square root | 135.355089 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 154 |
| Scientific notation | 1.8321 × |
18321 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand three hundred and twenty-one |
| Binary (base 2) | 100011110010001 |
| Octal (base 8) | 43621 |
| Hexadecimal (base 16) | 4791 |
| Base 3 | 221010120 |
| As time | 18321 seconds = 5 h 5 min 21 s |
Is 18321 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 (18321 ÷ 3 = 6107) | 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 | No (remainder 2) | 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 6) | 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 6) | 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 18321 a prime number?
No. 18321 = 3 × 31 × 197, so it is divisible by 3.
What are the factors of 18321?
1, 3, 31, 93, 197, 591, 6107, 18321.
What is 18321 in binary?
100011110010001 (hexadecimal 4791, octal 43621).
What is the square root of 18321?
About 135.3551.
Is 18321 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 18321?
18321 is a happy number: repeatedly adding the squares of its digits reaches 1.