The number 42872
42872 is a composite number with 16 divisors. Its prime factorisation is × 23 × 233. Divisors (16): 1, 2, 4, 8, 23, 46, 92, 184, 233, 466, 932, 1864, 5359, 10718, 21436, 42872.
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How to work it out
- 1
What is special about 42872: a Harshad number: divisible by its digit sum 23.
- 2
42872 is composite. Its prime factorisation is
- 3
The divisors add up to 84240; without 42872 itself that is 41368, so 42872 is deficient (41368 is less than 42872). Euler's totient φ(42872) = 20416 numbers up to 42872 share no factor with it.
- 4
The digits of 42872 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 194 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42872 = 2^{3} \times 23 \times 233 \]42872 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 84240 |
| Euler totient φ(n) | 20416 |
| Square | 1838008384 |
| Cube | 78799095438848 |
| Square root | 207.055548 (= 2√10718) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 194 |
| Scientific notation | 4.2872 × |
42872 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand eight hundred and seventy-two |
| Binary (base 2) | 1010011101111000 |
| Octal (base 8) | 123570 |
| Hexadecimal (base 16) | A778 |
| Base 3 | 2011210212 |
| As time | 42872 seconds = 11 h 54 min 32 s |
Is 42872 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42872 ÷ 2 = 21436) | 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 | Yes (42872 ÷ 4 = 10718) | 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 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 | Yes (42872 ÷ 8 = 5359) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | 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 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42872 a prime number?
No. 42872 = × 23 × 233, so it is divisible by 2.
What are the factors of 42872?
1, 2, 4, 8, 23, 46, 92, 184, 233, 466, 932, 1864, 5359, 10718, 21436, 42872.
What is 42872 in binary?
1010011101111000 (hexadecimal A778, octal 123570).
What is the square root of 42872?
About 207.0555, exactly 2√10718.
Is 42872 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 42872?
42872 is a Harshad number: divisible by its digit sum 23.