The number 42838
42838 is a composite number with 4 divisors. Its prime factorisation is 2 × 21419. Divisors (4): 1, 2, 21419, 42838.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42838: a semiprime: 2 × 21419, the product of two primes.
- 2
42838 is composite. Its prime factorisation is
- 3
The divisors add up to 64260; without 42838 itself that is 21422, so 42838 is deficient (21422 is less than 42838). Euler's totient φ(42838) = 21418 numbers up to 42838 share no factor with it.
- 4
The digits of 42838 add up to 25, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 101 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42838 = 2 \times 21419 \]
42838 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 64260 |
| Euler totient φ(n) | 21418 |
| Square | 1835094244 |
| Cube | 78611767224472 |
| Square root | 206.973428 |
| Digit sum / digital root | 25 / 7 |
| Collatz steps to 1 | 101 |
| Scientific notation | 4.2838 × |
42838 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand eight hundred and thirty-eight |
| Binary (base 2) | 1010011101010110 |
| Octal (base 8) | 123526 |
| Hexadecimal (base 16) | A756 |
| Base 3 | 2011202121 |
| As time | 42838 seconds = 11 h 53 min 58 s |
Is 42838 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42838 ÷ 2 = 21419) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42838 a prime number?
No. 42838 = 2 × 21419, so it is divisible by 2.
What are the factors of 42838?
1, 2, 21419, 42838.
What is 42838 in binary?
1010011101010110 (hexadecimal A756, octal 123526).
What is the square root of 42838?
About 206.9734.
Is 42838 divisible by 3?
No. Its digits add up to 25, which is not a multiple of 3.
What is special about the number 42838?
42838 is a semiprime: 2 × 21419, the product of two primes.