The number 18008
18008 is a composite number with 8 divisors. Its prime factorisation is × 2251. Divisors (8): 1, 2, 4, 8, 2251, 4502, 9004, 18008.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18008: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18008 is composite. Its prime factorisation is
- 3
The divisors add up to 33780; without 18008 itself that is 15772, so 18008 is deficient (15772 is less than 18008). Euler's totient φ(18008) = 9000 numbers up to 18008 share no factor with it.
- 4
The digits of 18008 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 40 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18008 = 2^{3} \times 2251 \]18008 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 33780 |
| Euler totient φ(n) | 9000 |
| Square | 324288064 |
| Cube | 5839779456512 |
| Square root | 134.193890 (= 2√4502) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 40 |
| Scientific notation | 1.8008 × |
18008 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand and eight |
| Binary (base 2) | 100011001011000 |
| Octal (base 8) | 43130 |
| Hexadecimal (base 16) | 4658 |
| Base 3 | 220200222 |
| As time | 18008 seconds = 5 h 0 min 8 s |
Is 18008 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (18008 ÷ 2 = 9004) | 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 | Yes (18008 ÷ 4 = 4502) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 | Yes (18008 ÷ 8 = 2251) | 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 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18008 a prime number?
No. 18008 = × 2251, so it is divisible by 2.
What are the factors of 18008?
1, 2, 4, 8, 2251, 4502, 9004, 18008.
What is 18008 in binary?
100011001011000 (hexadecimal 4658, octal 43130).
What is the square root of 18008?
About 134.1939, exactly 2√4502.
Is 18008 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 18008?
18008 is a happy number: repeatedly adding the squares of its digits reaches 1.