The number 42128
42128 is a composite number with 10 divisors. Its prime factorisation is × 2633. Divisors (10): 1, 2, 4, 8, 16, 2633, 5266, 10532, 21064, 42128.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42128 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42128 is composite. Its prime factorisation is
- 3
The divisors add up to 81654; without 42128 itself that is 39526, so 42128 is deficient (39526 is less than 42128). Euler's totient φ(42128) = 21056 numbers up to 42128 share no factor with it.
- 4
The digits of 42128 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 44 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42128 = 2^{4} \times 2633 \]42128 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 10 |
| Sum of divisors | 81654 |
| Euler totient φ(n) | 21056 |
| Square | 1774768384 |
| Cube | 74767442481152 |
| Square root | 205.251066 (= 4√2633) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 44 |
| Scientific notation | 4.2128 × |
42128 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand one hundred and twenty-eight |
| Binary (base 2) | 1010010010010000 |
| Octal (base 8) | 122220 |
| Hexadecimal (base 16) | A490 |
| Base 3 | 2010210022 |
| As time | 42128 seconds = 11 h 42 min 8 s |
Is 42128 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42128 ÷ 2 = 21064) | 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 (42128 ÷ 4 = 10532) | 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 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 (42128 ÷ 8 = 5266) | 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 8) | 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 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42128 a prime number?
No. 42128 = × 2633, so it is divisible by 2.
What are the factors of 42128?
1, 2, 4, 8, 16, 2633, 5266, 10532, 21064, 42128.
What is 42128 in binary?
1010010010010000 (hexadecimal A490, octal 122220).
What is the square root of 42128?
About 205.2511, exactly 4√2633.
Is 42128 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 42128?
It is a composite number with 10 divisors.