The number 47831
47831 is a composite number with 4 divisors. Its prime factorisation is 7 × 6833. Divisors (4): 1, 7, 6833, 47831.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 47831: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 7 × 6833, the product of two primes.
- 2
47831 is composite. Its prime factorisation is
- 3
The divisors add up to 54672; without 47831 itself that is 6841, so 47831 is deficient (6841 is less than 47831). Euler's totient φ(47831) = 40992 numbers up to 47831 share no factor with it.
- 4
The digits of 47831 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 145 steps to reach 1.
LaTeX source of the formulas on this page
\[ 47831 = 7 \times 6833 \]
47831 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 54672 |
| Euler totient φ(n) | 40992 |
| Square | 2287804561 |
| Cube | 109427979957191 |
| Square root | 218.702995 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 145 |
| Scientific notation | 4.7831 × |
47831 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand eight hundred and thirty-one |
| Binary (base 2) | 1011101011010111 |
| Octal (base 8) | 135327 |
| Hexadecimal (base 16) | BAD7 |
| Base 3 | 2102121112 |
| As time | 47831 seconds = 13 h 17 min 11 s |
Is 47831 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 2) | 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 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (47831 ÷ 7 = 6833) | 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 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | 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 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 47831 a prime number?
No. 47831 = 7 × 6833, so it is divisible by 7.
What are the factors of 47831?
1, 7, 6833, 47831.
What is 47831 in binary?
1011101011010111 (hexadecimal BAD7, octal 135327).
What is the square root of 47831?
About 218.7030.
Is 47831 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 47831?
47831 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 7 × 6833, the product of two primes.