The number 28807
28807 is the 3137th prime number and a binary palindrome (111000010000111). Its only divisors are 1 and 28807.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28807: the 3137th prime number; a binary palindrome (111000010000111).
- 2
28807 is prime, so its only factors are 1 and 28807. It is the 3137th prime; the next prime is 28813 and the one before is 28793.
- 3
The divisors add up to 28808; without 28807 itself that is 1, so 28807 is deficient (1 is less than 28807). Euler's totient φ(28807) = 28806 numbers up to 28807 share no factor with it.
- 4
The digits of 28807 add up to 25, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 165 steps to reach 1.
28807 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 28808 |
| Euler totient φ(n) | 28806 |
| Square | 829843249 |
| Cube | 23905294473943 |
| Square root | 169.726250 |
| Digit sum / digital root | 25 / 7 |
| Collatz steps to 1 | 165 |
| Scientific notation | 2.8807 × |
28807 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand eight hundred and seven |
| Binary (base 2) | 111000010000111 |
| Octal (base 8) | 70207 |
| Hexadecimal (base 16) | 7087 |
| Base 3 | 1110111221 |
| As time | 28807 seconds = 8 h 0 min 7 s |
Is 28807 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 3) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 7) | 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 7) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28807 a prime number?
Yes. 28807 is divisible only by 1 and itself.
What are the factors of 28807?
1, 28807.
What is 28807 in binary?
111000010000111 (hexadecimal 7087, octal 70207).
What is the square root of 28807?
About 169.7263.
Is 28807 divisible by 3?
No. Its digits add up to 25, which is not a multiple of 3.
What is special about the number 28807?
28807 is the 3137th prime number; a binary palindrome (111000010000111).