The number 18808
18808 is a composite number with 8 divisors. Its prime factorisation is × 2351. Divisors (8): 1, 2, 4, 8, 2351, 4702, 9404, 18808.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18808: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18808 is composite. Its prime factorisation is
- 3
The divisors add up to 35280; without 18808 itself that is 16472, so 18808 is deficient (16472 is less than 18808). Euler's totient φ(18808) = 9400 numbers up to 18808 share no factor with it.
- 4
The digits of 18808 add up to 25, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 61 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18808 = 2^{3} \times 2351 \]18808 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 35280 |
| Euler totient φ(n) | 9400 |
| Square | 353740864 |
| Cube | 6653158170112 |
| Square root | 137.142262 (= 2√4702) |
| Digit sum / digital root | 25 / 7 |
| Collatz steps to 1 | 61 |
| Scientific notation | 1.8808 × |
18808 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand eight hundred and eight |
| Binary (base 2) | 100100101111000 |
| Octal (base 8) | 44570 |
| Hexadecimal (base 16) | 4978 |
| Base 3 | 221210121 |
| As time | 18808 seconds = 5 h 13 min 28 s |
Is 18808 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (18808 ÷ 2 = 9404) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (18808 ÷ 4 = 4702) | 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 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 (18808 ÷ 8 = 2351) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | 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 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18808 a prime number?
No. 18808 = × 2351, so it is divisible by 2.
What are the factors of 18808?
1, 2, 4, 8, 2351, 4702, 9404, 18808.
What is 18808 in binary?
100100101111000 (hexadecimal 4978, octal 44570).
What is the square root of 18808?
About 137.1423, exactly 2√4702.
Is 18808 divisible by 3?
No. Its digits add up to 25, which is not a multiple of 3.
What is special about the number 18808?
18808 is a happy number: repeatedly adding the squares of its digits reaches 1.