The number 31842
31842 is a composite number with 24 divisors. Its prime factorisation is 2 × × 29 × 61. Divisors (24): 1, 2, 3, 6, 9, 18, 29, 58, 61, 87, 122, 174, 183, 261, 366, 522 … 31842.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31842: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.
- 2
31842 is composite. Its prime factorisation is
- 3
The divisors add up to 72540; without 31842 itself that is 40698, so 31842 is abundant (40698 is more than 31842). Euler's totient φ(31842) = 10080 numbers up to 31842 share no factor with it.
- 4
The digits of 31842 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 147 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31842 = 2 \times 3^{2} \times 29 \times 61 \]31842 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 72540 |
| Euler totient φ(n) | 10080 |
| Square | 1013912964 |
| Cube | 32285016599688 |
| Square root | 178.443268 (= 3√3538) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 147 |
| Scientific notation | 3.1842 × |
31842 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand eight hundred and forty-two |
| Binary (base 2) | 111110001100010 |
| Octal (base 8) | 76142 |
| Hexadecimal (base 16) | 7C62 |
| Base 3 | 1121200100 |
| As time | 31842 seconds = 8 h 50 min 42 s |
Is 31842 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31842 ÷ 2 = 15921) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (31842 ÷ 3 = 10614) | 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 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (31842 ÷ 6 = 5307) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (31842 ÷ 9 = 3538) | 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 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31842 a prime number?
No. 31842 = 2 × × 29 × 61, so it is divisible by 2.
What are the factors of 31842?
1, 2, 3, 6, 9, 18, 29, 58, 61, 87, 122, 174, 183, 261, 366, 522, 549, 1098, 1769, 3538, 5307, 10614, 15921, 31842.
What is 31842 in binary?
111110001100010 (hexadecimal 7C62, octal 76142).
What is the square root of 31842?
About 178.4433, exactly 3√3538.
Is 31842 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 31842?
31842 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.