The number 18209
18209 is a composite number with 4 divisors. Its prime factorisation is 131 × 139. Divisors (4): 1, 131, 139, 18209.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18209: a semiprime: 131 × 139, the product of two primes.
- 2
18209 is composite. Its prime factorisation is
- 3
The divisors add up to 18480; without 18209 itself that is 271, so 18209 is deficient (271 is less than 18209). Euler's totient φ(18209) = 17940 numbers up to 18209 share no factor with it.
- 4
The digits of 18209 add up to 20, 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
\[ 18209 = 131 \times 139 \]
18209 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 18480 |
| Euler totient φ(n) | 17940 |
| Square | 331567681 |
| Cube | 6037515903329 |
| Square root | 134.940728 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 48 |
| Scientific notation | 1.8209 × |
18209 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand two hundred and nine |
| Binary (base 2) | 100011100100001 |
| Octal (base 8) | 43441 |
| Hexadecimal (base 16) | 4721 |
| Base 3 | 220222102 |
| As time | 18209 seconds = 5 h 3 min 29 s |
Is 18209 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 | 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 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 4) | 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 18209 a prime number?
No. 18209 = 131 × 139, so it is divisible by 131.
What are the factors of 18209?
1, 131, 139, 18209.
What is 18209 in binary?
100011100100001 (hexadecimal 4721, octal 43441).
What is the square root of 18209?
About 134.9407.
Is 18209 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 18209?
18209 is a semiprime: 131 × 139, the product of two primes.