The number 18389
18389 is a composite number with 8 divisors. Its prime factorisation is 7 × 37 × 71. Divisors (8): 1, 7, 37, 71, 259, 497, 2627, 18389.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18389: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18389 is composite. Its prime factorisation is
- 3
The divisors add up to 21888; without 18389 itself that is 3499, so 18389 is deficient (3499 is less than 18389). Euler's totient φ(18389) = 15120 numbers up to 18389 share no factor with it.
- 4
The digits of 18389 add up to 29, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 48 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18389 = 7 \times 37 \times 71 \]
18389 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 21888 |
| Euler totient φ(n) | 15120 |
| Square | 338155321 |
| Cube | 6218338197869 |
| Square root | 135.606047 |
| Digit sum / digital root | 29 / 2 |
| Collatz steps to 1 | 48 |
| Scientific notation | 1.8389 × |
18389 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand three hundred and eighty-nine |
| Binary (base 2) | 100011111010101 |
| Octal (base 8) | 43725 |
| Hexadecimal (base 16) | 47D5 |
| Base 3 | 221020002 |
| As time | 18389 seconds = 5 h 6 min 29 s |
Is 18389 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 4) | 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 | Yes (18389 ÷ 7 = 2627) | 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 2) | 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 8) | 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 18389 a prime number?
No. 18389 = 7 × 37 × 71, so it is divisible by 7.
What are the factors of 18389?
1, 7, 37, 71, 259, 497, 2627, 18389.
What is 18389 in binary?
100011111010101 (hexadecimal 47D5, octal 43725).
What is the square root of 18389?
About 135.6060.
Is 18389 divisible by 3?
No. Its digits add up to 29, which is not a multiple of 3.
What is special about the number 18389?
18389 is a happy number: repeatedly adding the squares of its digits reaches 1.