The number 808
808 is a palindrome: it reads 808 backwards too. Its prime factorisation is × 101. Divisors (8): 1, 2, 4, 8, 101, 202, 404, 808.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 808: a palindrome: it reads 808 backwards too.
- 2
808 is composite. Its prime factorisation is
- 3
The divisors add up to 1530; without 808 itself that is 722, so 808 is deficient (722 is less than 808). Euler's totient φ(808) = 400 numbers up to 808 share no factor with it.
- 4
The digits of 808 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 28 steps to reach 1.
LaTeX source of the formulas on this page
\[ 808 = 2^{3} \times 101 \]808 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 1530 |
| Euler totient φ(n) | 400 |
| Square | 652864 |
| Cube | 527514112 |
| Square root | 28.425341 (= 2√202) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 28 |
| Scientific notation | 8.08 × |
808 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and eight |
| Roman numerals | DCCCVIII |
| Binary (base 2) | 1100101000 |
| Octal (base 8) | 1450 |
| Hexadecimal (base 16) | 328 |
| Base 3 | 1002221 |
| As time | 808 seconds = 13 min 28 s |
Is 808 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (808 ÷ 2 = 404) | 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 (808 ÷ 4 = 202) | 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 3) | 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 (808 ÷ 8 = 101) | 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 5) | 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 808 a prime number?
No. 808 = × 101, so it is divisible by 2.
What are the factors of 808?
1, 2, 4, 8, 101, 202, 404, 808.
What is 808 in binary?
1100101000 (hexadecimal 328, octal 1450).
What is the square root of 808?
About 28.4253, exactly 2√202.
What is 808 in Roman numerals?
DCCCVIII.
Is 808 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 808?
808 is a palindrome: it reads 808 backwards too.