The number 31841
31841 is a composite number with 4 divisors. Its prime factorisation is 17 × 1873. Divisors (4): 1, 17, 1873, 31841.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31841: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 17; a semiprime: 17 × 1873, the product of two primes.
- 2
31841 is composite. Its prime factorisation is
- 3
The divisors add up to 33732; without 31841 itself that is 1891, so 31841 is deficient (1891 is less than 31841). Euler's totient φ(31841) = 29952 numbers up to 31841 share no factor with it.
- 4
The digits of 31841 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 103 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31841 = 17 \times 1873 \]
31841 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 33732 |
| Euler totient φ(n) | 29952 |
| Square | 1013849281 |
| Cube | 32281974956321 |
| Square root | 178.440466 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 103 |
| Scientific notation | 3.1841 × |
31841 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand eight hundred and forty-one |
| Binary (base 2) | 111110001100001 |
| Octal (base 8) | 76141 |
| Hexadecimal (base 16) | 7C61 |
| Base 3 | 1121200022 |
| As time | 31841 seconds = 8 h 50 min 41 s |
Is 31841 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 1) | 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 | No (remainder 5) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | 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 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31841 a prime number?
No. 31841 = 17 × 1873, so it is divisible by 17.
What are the factors of 31841?
1, 17, 1873, 31841.
What is 31841 in binary?
111110001100001 (hexadecimal 7C61, octal 76141).
What is the square root of 31841?
About 178.4405.
Is 31841 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 31841?
31841 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 17; a semiprime: 17 × 1873, the product of two primes.