The number 806
806 is a composite number with 8 divisors. Its prime factorisation is 2 × 13 × 31. Divisors (8): 1, 2, 13, 26, 31, 62, 403, 806.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 806: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
806 is composite. Its prime factorisation is
- 3
The divisors add up to 1344; without 806 itself that is 538, so 806 is deficient (538 is less than 806). Euler's totient φ(806) = 360 numbers up to 806 share no factor with it.
- 4
The digits of 806 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 20 steps to reach 1.
LaTeX source of the formulas on this page
\[ 806 = 2 \times 13 \times 31 \]
806 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 1344 |
| Euler totient φ(n) | 360 |
| Square | 649636 |
| Cube | 523606616 |
| Square root | 28.390139 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 20 |
| Scientific notation | 8.06 × |
806 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and six |
| Roman numerals | DCCCVI |
| Binary (base 2) | 1100100110 |
| Octal (base 8) | 1446 |
| Hexadecimal (base 16) | 326 |
| Base 3 | 1002212 |
| As time | 806 seconds = 13 min 26 s |
Is 806 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (806 ÷ 2 = 403) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | 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 1) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 6) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 806 a prime number?
No. 806 = 2 × 13 × 31, so it is divisible by 2.
What are the factors of 806?
1, 2, 13, 26, 31, 62, 403, 806.
What is 806 in binary?
1100100110 (hexadecimal 326, octal 1446).
What is the square root of 806?
About 28.3901.
What is 806 in Roman numerals?
DCCCVI.
Is 806 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 806?
806 is a happy number: repeatedly adding the squares of its digits reaches 1.