The number 42381
42381 is a composite number with 12 divisors. Its prime factorisation is × 17 × 277. Divisors (12): 1, 3, 9, 17, 51, 153, 277, 831, 2493, 4709, 14127, 42381.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42381: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
42381 is composite. Its prime factorisation is
- 3
The divisors add up to 65052; without 42381 itself that is 22671, so 42381 is deficient (22671 is less than 42381). Euler's totient φ(42381) = 26496 numbers up to 42381 share no factor with it.
- 4
The digits of 42381 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 101 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42381 = 3^{2} \times 17 \times 277 \]42381 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 65052 |
| Euler totient φ(n) | 26496 |
| Square | 1796149161 |
| Cube | 76122597592341 |
| Square root | 205.866462 (= 3√4709) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 101 |
| Scientific notation | 4.2381 × |
42381 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand three hundred and eighty-one |
| Binary (base 2) | 1010010110001101 |
| Octal (base 8) | 122615 |
| Hexadecimal (base 16) | A58D |
| Base 3 | 2011010200 |
| As time | 42381 seconds = 11 h 46 min 21 s |
Is 42381 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 | Yes (42381 ÷ 3 = 14127) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (42381 ÷ 9 = 4709) | 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 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42381 a prime number?
No. 42381 = × 17 × 277, so it is divisible by 3.
What are the factors of 42381?
1, 3, 9, 17, 51, 153, 277, 831, 2493, 4709, 14127, 42381.
What is 42381 in binary?
1010010110001101 (hexadecimal A58D, octal 122615).
What is the square root of 42381?
About 205.8665, exactly 3√4709.
Is 42381 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 42381?
42381 is a happy number: repeatedly adding the squares of its digits reaches 1.