The number 42857
42857 is a composite number with 4 divisors. Its prime factorisation is 17 × 2521. Divisors (4): 1, 17, 2521, 42857.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42857: a semiprime: 17 × 2521, the product of two primes.
- 2
42857 is composite. Its prime factorisation is
- 3
The divisors add up to 45396; without 42857 itself that is 2539, so 42857 is deficient (2539 is less than 42857). Euler's totient φ(42857) = 40320 numbers up to 42857 share no factor with it.
- 4
The digits of 42857 add up to 26, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 49 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42857 = 17 \times 2521 \]
42857 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 45396 |
| Euler totient φ(n) | 40320 |
| Square | 1836722449 |
| Cube | 78716413996793 |
| Square root | 207.019323 |
| Digit sum / digital root | 26 / 8 |
| Collatz steps to 1 | 49 |
| Scientific notation | 4.2857 × |
42857 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand eight hundred and fifty-seven |
| Binary (base 2) | 1010011101101001 |
| Octal (base 8) | 123551 |
| Hexadecimal (base 16) | A769 |
| Base 3 | 2011210022 |
| As time | 42857 seconds = 11 h 54 min 17 s |
Is 42857 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 2) | 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 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 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 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | 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 42857 a prime number?
No. 42857 = 17 × 2521, so it is divisible by 17.
What are the factors of 42857?
1, 17, 2521, 42857.
What is 42857 in binary?
1010011101101001 (hexadecimal A769, octal 123551).
What is the square root of 42857?
About 207.0193.
Is 42857 divisible by 3?
No. Its digits add up to 26, which is not a multiple of 3.
What is special about the number 42857?
42857 is a semiprime: 17 × 2521, the product of two primes.