The number 812
812 is a composite number with 12 divisors. Its prime factorisation is × 7 × 29. Divisors (12): 1, 2, 4, 7, 14, 28, 29, 58, 116, 203, 406, 812.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
812 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
812 is composite. Its prime factorisation is
- 3
The divisors add up to 1680; without 812 itself that is 868, so 812 is abundant (868 is more than 812). Euler's totient φ(812) = 336 numbers up to 812 share no factor with it.
- 4
The digits of 812 add up to 11, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 41 steps to reach 1.
LaTeX source of the formulas on this page
\[ 812 = 2^{2} \times 7 \times 29 \]812 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 1680 |
| Euler totient φ(n) | 336 |
| Square | 659344 |
| Cube | 535387328 |
| Square root | 28.495614 (= 2√203) |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 41 |
| Scientific notation | 8.12 × |
812 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and twelve |
| Roman numerals | DCCCXII |
| Binary (base 2) | 1100101100 |
| Octal (base 8) | 1454 |
| Hexadecimal (base 16) | 32C |
| Base 3 | 1010002 |
| As time | 812 seconds = 13 min 32 s |
Is 812 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (812 ÷ 2 = 406) | 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 (812 ÷ 4 = 203) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | 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 | Yes (812 ÷ 7 = 116) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | 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 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 812 a prime number?
No. 812 = × 7 × 29, so it is divisible by 2.
What are the factors of 812?
1, 2, 4, 7, 14, 28, 29, 58, 116, 203, 406, 812.
What is 812 in binary?
1100101100 (hexadecimal 32C, octal 1454).
What is the square root of 812?
About 28.4956, exactly 2√203.
What is 812 in Roman numerals?
DCCCXII.
Is 812 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 812?
It is a composite number with 12 divisors.