The number 13391
13391 is a composite number with 4 divisors. Its prime factorisation is 7 × 1913. Divisors (4): 1, 7, 1913, 13391.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 13391: a semiprime: 7 × 1913, the product of two primes.
- 2
13391 is composite. Its prime factorisation is
- 3
The divisors add up to 15312; without 13391 itself that is 1921, so 13391 is deficient (1921 is less than 13391). Euler's totient φ(13391) = 11472 numbers up to 13391 share no factor with it.
- 4
The digits of 13391 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 45 steps to reach 1.
LaTeX source of the formulas on this page
\[ 13391 = 7 \times 1913 \]
13391 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 15312 |
| Euler totient φ(n) | 11472 |
| Square | 179318881 |
| Cube | 2401259135471 |
| Square root | 115.719488 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 45 |
| Scientific notation | 1.3391 × |
13391 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand three hundred and ninety-one |
| Binary (base 2) | 11010001001111 |
| Octal (base 8) | 32117 |
| Hexadecimal (base 16) | 344F |
| Base 3 | 200100222 |
| As time | 13391 seconds = 3 h 43 min 11 s |
Is 13391 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 3) | 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 | Yes (13391 ÷ 7 = 1913) | 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 8) | 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 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 13391 a prime number?
No. 13391 = 7 × 1913, so it is divisible by 7.
What are the factors of 13391?
1, 7, 1913, 13391.
What is 13391 in binary?
11010001001111 (hexadecimal 344F, octal 32117).
What is the square root of 13391?
About 115.7195.
Is 13391 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 13391?
13391 is a semiprime: 7 × 1913, the product of two primes.