The number 28742
28742 is a composite number with 8 divisors. Its prime factorisation is 2 × 7 × 2053. Divisors (8): 1, 2, 7, 14, 2053, 4106, 14371, 28742.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
28742 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
28742 is composite. Its prime factorisation is
- 3
The divisors add up to 49296; without 28742 itself that is 20554, so 28742 is deficient (20554 is less than 28742). Euler's totient φ(28742) = 12312 numbers up to 28742 share no factor with it.
- 4
The digits of 28742 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 72 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28742 = 2 \times 7 \times 2053 \]
28742 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 49296 |
| Euler totient φ(n) | 12312 |
| Square | 826102564 |
| Cube | 23743839894488 |
| Square root | 169.534657 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 72 |
| Scientific notation | 2.8742 × |
28742 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand seven hundred and forty-two |
| Binary (base 2) | 111000001000110 |
| Octal (base 8) | 70106 |
| Hexadecimal (base 16) | 7046 |
| Base 3 | 1110102112 |
| As time | 28742 seconds = 7 h 59 min 2 s |
Is 28742 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (28742 ÷ 2 = 14371) | 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 2) | 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 | Yes (28742 ÷ 7 = 4106) | 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 6) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28742 a prime number?
No. 28742 = 2 × 7 × 2053, so it is divisible by 2.
What are the factors of 28742?
1, 2, 7, 14, 2053, 4106, 14371, 28742.
What is 28742 in binary?
111000001000110 (hexadecimal 7046, octal 70106).
What is the square root of 28742?
About 169.5347.
Is 28742 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 28742?
It is a composite number with 8 divisors.