The number 1808
1808 is a composite number with 10 divisors. Its prime factorisation is × 113. Divisors (10): 1, 2, 4, 8, 16, 113, 226, 452, 904, 1808.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1808: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
1808 is composite. Its prime factorisation is
- 3
The divisors add up to 3534; without 1808 itself that is 1726, so 1808 is deficient (1726 is less than 1808). Euler's totient φ(1808) = 896 numbers up to 1808 share no factor with it.
- 4
The digits of 1808 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 16 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1808 = 2^{4} \times 113 \]1808 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 10 |
| Sum of divisors | 3534 |
| Euler totient φ(n) | 896 |
| Square | 3268864 |
| Cube | 5910106112 |
| Square root | 42.520583 (= 4√113) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 16 |
| Scientific notation | 1.808 × |
1808 in other forms
| Form | Value |
|---|---|
| In words | one thousand eight hundred and eight |
| Roman numerals | MDCCCVIII |
| Binary (base 2) | 11100010000 |
| Octal (base 8) | 3420 |
| Hexadecimal (base 16) | 710 |
| Base 3 | 2110222 |
| As time | 1808 seconds = 30 min 8 s |
Is 1808 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (1808 ÷ 2 = 904) | 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 (1808 ÷ 4 = 452) | 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 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 | Yes (1808 ÷ 8 = 226) | 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 4) | 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 1808 a prime number?
No. 1808 = × 113, so it is divisible by 2.
What are the factors of 1808?
1, 2, 4, 8, 16, 113, 226, 452, 904, 1808.
What is 1808 in binary?
11100010000 (hexadecimal 710, octal 3420).
What is the square root of 1808?
About 42.5206, exactly 4√113.
What is 1808 in Roman numerals?
MDCCCVIII.
Is 1808 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 1808?
1808 is a happy number: repeatedly adding the squares of its digits reaches 1.