The number 42728
42728 is a composite number with 24 divisors. Its prime factorisation is × × 109. Divisors (24): 1, 2, 4, 7, 8, 14, 28, 49, 56, 98, 109, 196, 218, 392, 436, 763 … 42728.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42728 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42728 is composite. Its prime factorisation is
- 3
The divisors add up to 94050; without 42728 itself that is 51322, so 42728 is abundant (51322 is more than 42728). Euler's totient φ(42728) = 18144 numbers up to 42728 share no factor with it.
- 4
The digits of 42728 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 150 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42728 = 2^{3} \times 7^{2} \times 109 \]42728 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 94050 |
| Euler totient φ(n) | 18144 |
| Square | 1825681984 |
| Cube | 78007739812352 |
| Square root | 206.707523 (= 14√218) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 150 |
| Scientific notation | 4.2728 × |
42728 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand seven hundred and twenty-eight |
| Binary (base 2) | 1010011011101000 |
| Octal (base 8) | 123350 |
| Hexadecimal (base 16) | A6E8 |
| Base 3 | 2011121112 |
| As time | 42728 seconds = 11 h 52 min 8 s |
Is 42728 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42728 ÷ 2 = 21364) | 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 (42728 ÷ 4 = 10682) | 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 | Yes (42728 ÷ 7 = 6104) | 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 (42728 ÷ 8 = 5341) | 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 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 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42728 a prime number?
No. 42728 = × × 109, so it is divisible by 2.
What are the factors of 42728?
1, 2, 4, 7, 8, 14, 28, 49, 56, 98, 109, 196, 218, 392, 436, 763, 872, 1526, 3052, 5341, 6104, 10682, 21364, 42728.
What is 42728 in binary?
1010011011101000 (hexadecimal A6E8, octal 123350).
What is the square root of 42728?
About 206.7075, exactly 14√218.
Is 42728 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 42728?
It is a composite number with 24 divisors.