The number 28309
28309 is a twin prime (28307 and 28309 are both prime) and the 3084th prime number. Its only divisors are 1 and 28309.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28309: a twin prime (28307 and 28309 are both prime); the 3084th prime number.
- 2
28309 is prime, so its only factors are 1 and 28309. It is the 3084th prime; the next prime is 28319 and the one before is 28307.
- 3
The divisors add up to 28310; without 28309 itself that is 1, so 28309 is deficient (1 is less than 28309). Euler's totient φ(28309) = 28308 numbers up to 28309 share no factor with it.
- 4
The digits of 28309 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 59 steps to reach 1.
28309 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 28310 |
| Euler totient φ(n) | 28308 |
| Square | 801399481 |
| Cube | 22686817907629 |
| Square root | 168.252786 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 59 |
| Scientific notation | 2.8309 × |
28309 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand three hundred and nine |
| Binary (base 2) | 110111010010101 |
| Octal (base 8) | 67225 |
| Hexadecimal (base 16) | 6E95 |
| Base 3 | 1102211111 |
| As time | 28309 seconds = 7 h 51 min 49 s |
Is 28309 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 4) | 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 1) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 6) | 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 28309 a prime number?
Yes. 28309 is divisible only by 1 and itself.
What are the factors of 28309?
1, 28309.
What is 28309 in binary?
110111010010101 (hexadecimal 6E95, octal 67225).
What is the square root of 28309?
About 168.2528.
Is 28309 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 28309?
28309 is a twin prime (28307 and 28309 are both prime); the 3084th prime number.