The number 28739
28739 is a composite number with 4 divisors. Its prime factorisation is 29 × 991. Divisors (4): 1, 29, 991, 28739.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28739: a Harshad number: divisible by its digit sum 29; a semiprime: 29 × 991, the product of two primes.
- 2
28739 is composite. Its prime factorisation is
- 3
The divisors add up to 29760; without 28739 itself that is 1021, so 28739 is deficient (1021 is less than 28739). Euler's totient φ(28739) = 27720 numbers up to 28739 share no factor with it.
- 4
The digits of 28739 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 152 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28739 = 29 \times 991 \]
28739 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 29760 |
| Euler totient φ(n) | 27720 |
| Square | 825930121 |
| Cube | 23736405747419 |
| Square root | 169.525809 |
| Digit sum / digital root | 29 / 2 |
| Collatz steps to 1 | 152 |
| Scientific notation | 2.8739 × |
28739 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand seven hundred and thirty-nine |
| Binary (base 2) | 111000001000011 |
| Octal (base 8) | 70103 |
| Hexadecimal (base 16) | 7043 |
| Base 3 | 1110102102 |
| As time | 28739 seconds = 7 h 58 min 59 s |
Is 28739 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | 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 3) | 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 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28739 a prime number?
No. 28739 = 29 × 991, so it is divisible by 29.
What are the factors of 28739?
1, 29, 991, 28739.
What is 28739 in binary?
111000001000011 (hexadecimal 7043, octal 70103).
What is the square root of 28739?
About 169.5258.
Is 28739 divisible by 3?
No. Its digits add up to 29, which is not a multiple of 3.
What is special about the number 28739?
28739 is a Harshad number: divisible by its digit sum 29; a semiprime: 29 × 991, the product of two primes.