The number 13681
13681 is a twin prime (13679 and 13681 are both prime) and the 1616th prime number. Its only divisors are 1 and 13681.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 13681: a twin prime (13679 and 13681 are both prime); the 1616th prime number.
- 2
13681 is prime, so its only factors are 1 and 13681. It is the 1616th prime; the next prime is 13687 and the one before is 13679.
- 3
The divisors add up to 13682; without 13681 itself that is 1, so 13681 is deficient (1 is less than 13681). Euler's totient φ(13681) = 13680 numbers up to 13681 share no factor with it.
- 4
The digits of 13681 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 58 steps to reach 1.
13681 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 13682 |
| Euler totient φ(n) | 13680 |
| Square | 187169761 |
| Cube | 2560669500241 |
| Square root | 116.965807 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 58 |
| Scientific notation | 1.3681 × |
13681 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand six hundred and eighty-one |
| Binary (base 2) | 11010101110001 |
| Octal (base 8) | 32561 |
| Hexadecimal (base 16) | 3571 |
| Base 3 | 200202201 |
| As time | 13681 seconds = 3 h 48 min 1 s |
Is 13681 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 3) | 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 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | 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 13681 a prime number?
Yes. 13681 is divisible only by 1 and itself.
What are the factors of 13681?
1, 13681.
What is 13681 in binary?
11010101110001 (hexadecimal 3571, octal 32561).
What is the square root of 13681?
About 116.9658.
Is 13681 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 13681?
13681 is a twin prime (13679 and 13681 are both prime); the 1616th prime number.