The number 847
847 is a composite number with 6 divisors. Its prime factorisation is 7 × . Divisors (6): 1, 7, 11, 77, 121, 847.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 847: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
847 is composite. Its prime factorisation is
- 3
The divisors add up to 1064; without 847 itself that is 217, so 847 is deficient (217 is less than 847). Euler's totient φ(847) = 660 numbers up to 847 share no factor with it.
- 4
The digits of 847 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 33 steps to reach 1.
LaTeX source of the formulas on this page
\[ 847 = 7 \times 11^{2} \]847 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 1064 |
| Euler totient φ(n) | 660 |
| Square | 717409 |
| Cube | 607645423 |
| Square root | 29.103264 (= 11√7) |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 33 |
| Scientific notation | 8.47 × |
847 in other forms
| Form | Value |
|---|---|
| In words | eight hundred and forty-seven |
| Roman numerals | DCCCXLVII |
| Binary (base 2) | 1101001111 |
| Octal (base 8) | 1517 |
| Hexadecimal (base 16) | 34F |
| Base 3 | 1011101 |
| As time | 847 seconds = 14 min 7 s |
Is 847 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 | No (remainder 3) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (847 ÷ 7 = 121) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (847 ÷ 11 = 77) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 847 a prime number?
No. 847 = 7 × , so it is divisible by 7.
What are the factors of 847?
1, 7, 11, 77, 121, 847.
What is 847 in binary?
1101001111 (hexadecimal 34F, octal 1517).
What is the square root of 847?
About 29.1033, exactly 11√7.
What is 847 in Roman numerals?
DCCCXLVII.
Is 847 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 847?
847 is a happy number: repeatedly adding the squares of its digits reaches 1.