The number 42788
42788 is a composite number with 12 divisors. Its prime factorisation is × 19 × 563. Divisors (12): 1, 2, 4, 19, 38, 76, 563, 1126, 2252, 10697, 21394, 42788.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42788 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42788 is composite. Its prime factorisation is
- 3
The divisors add up to 78960; without 42788 itself that is 36172, so 42788 is deficient (36172 is less than 42788). Euler's totient φ(42788) = 20232 numbers up to 42788 share no factor with it.
- 4
The digits of 42788 add up to 29, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 194 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42788 = 2^{2} \times 19 \times 563 \]42788 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 78960 |
| Euler totient φ(n) | 20232 |
| Square | 1830812944 |
| Cube | 78336824247872 |
| Square root | 206.852605 (= 2√10697) |
| Digit sum / digital root | 29 / 2 |
| Collatz steps to 1 | 194 |
| Scientific notation | 4.2788 × |
42788 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand seven hundred and eighty-eight |
| Binary (base 2) | 1010011100100100 |
| Octal (base 8) | 123444 |
| Hexadecimal (base 16) | A724 |
| Base 3 | 2011200202 |
| As time | 42788 seconds = 11 h 53 min 8 s |
Is 42788 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42788 ÷ 2 = 21394) | 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 (42788 ÷ 4 = 10697) | 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 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 | No (remainder 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | 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 42788 a prime number?
No. 42788 = × 19 × 563, so it is divisible by 2.
What are the factors of 42788?
1, 2, 4, 19, 38, 76, 563, 1126, 2252, 10697, 21394, 42788.
What is 42788 in binary?
1010011100100100 (hexadecimal A724, octal 123444).
What is the square root of 42788?
About 206.8526, exactly 2√10697.
Is 42788 divisible by 3?
No. Its digits add up to 29, which is not a multiple of 3.
What is special about the number 42788?
It is a composite number with 12 divisors.