The number 47381
47381 is the 4885th prime number. Its only divisors are 1 and 47381.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 47381: the 4885th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
47381 is prime, so its only factors are 1 and 47381. It is the 4885th prime; the next prime is 47387 and the one before is 47363.
- 3
The divisors add up to 47382; without 47381 itself that is 1, so 47381 is deficient (1 is less than 47381). Euler's totient φ(47381) = 47380 numbers up to 47381 share no factor with it.
- 4
The digits of 47381 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 39 steps to reach 1.
47381 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 47382 |
| Euler totient φ(n) | 47380 |
| Square | 2244959161 |
| Cube | 106368410007341 |
| Square root | 217.671771 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 39 |
| Scientific notation | 4.7381 × |
47381 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand three hundred and eighty-one |
| Binary (base 2) | 1011100100010101 |
| Octal (base 8) | 134425 |
| Hexadecimal (base 16) | B915 |
| Base 3 | 2101222212 |
| As time | 47381 seconds = 13 h 9 min 41 s |
Is 47381 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 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 5) | 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 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 47381 a prime number?
Yes. 47381 is divisible only by 1 and itself.
What are the factors of 47381?
1, 47381.
What is 47381 in binary?
1011100100010101 (hexadecimal B915, octal 134425).
What is the square root of 47381?
About 217.6718.
Is 47381 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 47381?
47381 is the 4885th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.