The number 47809
47809 is a twin prime (47807 and 47809 are both prime) and the 4929th prime number. Its only divisors are 1 and 47809.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 47809: a twin prime (47807 and 47809 are both prime); the 4929th prime number.
- 2
47809 is prime, so its only factors are 1 and 47809. It is the 4929th prime; the next prime is 47819 and the one before is 47807.
- 3
The divisors add up to 47810; without 47809 itself that is 1, so 47809 is deficient (1 is less than 47809). Euler's totient φ(47809) = 47808 numbers up to 47809 share no factor with it.
- 4
The digits of 47809 add up to 28, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 52 steps to reach 1.
47809 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 47810 |
| Euler totient φ(n) | 47808 |
| Square | 2285700481 |
| Cube | 109277054296129 |
| Square root | 218.652693 |
| Digit sum / digital root | 28 / 1 |
| Collatz steps to 1 | 52 |
| Scientific notation | 4.7809 × |
47809 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand eight hundred and nine |
| Binary (base 2) | 1011101011000001 |
| Octal (base 8) | 135301 |
| Hexadecimal (base 16) | BAC1 |
| Base 3 | 2102120201 |
| As time | 47809 seconds = 13 h 16 min 49 s |
Is 47809 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 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 1) | 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 3) | 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 47809 a prime number?
Yes. 47809 is divisible only by 1 and itself.
What are the factors of 47809?
1, 47809.
What is 47809 in binary?
1011101011000001 (hexadecimal BAC1, octal 135301).
What is the square root of 47809?
About 218.6527.
Is 47809 divisible by 3?
No. Its digits add up to 28, which is not a multiple of 3.
What is special about the number 47809?
47809 is a twin prime (47807 and 47809 are both prime); the 4929th prime number.