The number 13981
13981 is a composite number with 8 divisors. Its prime factorisation is 11 × 31 × 41. Divisors (8): 1, 11, 31, 41, 341, 451, 1271, 13981.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
13981 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
13981 is composite. Its prime factorisation is
- 3
The divisors add up to 16128; without 13981 itself that is 2147, so 13981 is deficient (2147 is less than 13981). Euler's totient φ(13981) = 12000 numbers up to 13981 share no factor with it.
- 4
The digits of 13981 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 58 steps to reach 1.
LaTeX source of the formulas on this page
\[ 13981 = 11 \times 31 \times 41 \]
13981 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 16128 |
| Euler totient φ(n) | 12000 |
| Square | 195468361 |
| Cube | 2732843155141 |
| Square root | 118.241279 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 58 |
| Scientific notation | 1.3981 × |
13981 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand nine hundred and eighty-one |
| Binary (base 2) | 11011010011101 |
| Octal (base 8) | 33235 |
| Hexadecimal (base 16) | 369D |
| Base 3 | 201011211 |
| As time | 13981 seconds = 3 h 53 min 1 s |
Is 13981 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 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 | Yes (13981 ÷ 11 = 1271) | 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 13981 a prime number?
No. 13981 = 11 × 31 × 41, so it is divisible by 11.
What are the factors of 13981?
1, 11, 31, 41, 341, 451, 1271, 13981.
What is 13981 in binary?
11011010011101 (hexadecimal 369D, octal 33235).
What is the square root of 13981?
About 118.2413.
Is 13981 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 13981?
It is a composite number with 8 divisors.