The number 28321
28321 is a composite number with 4 divisors. Its prime factorisation is 127 × 223. Divisors (4): 1, 127, 223, 28321.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28321: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 127 × 223, the product of two primes.
- 2
28321 is composite. Its prime factorisation is
- 3
The divisors add up to 28672; without 28321 itself that is 351, so 28321 is deficient (351 is less than 28321). Euler's totient φ(28321) = 27972 numbers up to 28321 share no factor with it.
- 4
The digits of 28321 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 59 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28321 = 127 \times 223 \]
28321 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 28672 |
| Euler totient φ(n) | 27972 |
| Square | 802079041 |
| Cube | 22715680520161 |
| Square root | 168.288443 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 59 |
| Scientific notation | 2.8321 × |
28321 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand three hundred and twenty-one |
| Binary (base 2) | 110111010100001 |
| Octal (base 8) | 67241 |
| Hexadecimal (base 16) | 6EA1 |
| Base 3 | 1102211221 |
| As time | 28321 seconds = 7 h 52 min 1 s |
Is 28321 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 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28321 a prime number?
No. 28321 = 127 × 223, so it is divisible by 127.
What are the factors of 28321?
1, 127, 223, 28321.
What is 28321 in binary?
110111010100001 (hexadecimal 6EA1, octal 67241).
What is the square root of 28321?
About 168.2884.
Is 28321 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 28321?
28321 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 127 × 223, the product of two primes.