The number 13987
13987 is a composite number with 4 divisors. Its prime factorisation is 71 × 197. Divisors (4): 1, 71, 197, 13987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 13987: a semiprime: 71 × 197, the product of two primes.
- 2
13987 is composite. Its prime factorisation is
- 3
The divisors add up to 14256; without 13987 itself that is 269, so 13987 is deficient (269 is less than 13987). Euler's totient φ(13987) = 13720 numbers up to 13987 share no factor with it.
- 4
The digits of 13987 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 107 steps to reach 1.
LaTeX source of the formulas on this page
\[ 13987 = 71 \times 197 \]
13987 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 14256 |
| Euler totient φ(n) | 13720 |
| Square | 195636169 |
| Cube | 2736363095803 |
| Square root | 118.266648 |
| Digit sum / digital root | 28 / 1 |
| Collatz steps to 1 | 107 |
| Scientific notation | 1.3987 × |
13987 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand nine hundred and eighty-seven |
| Binary (base 2) | 11011010100011 |
| Octal (base 8) | 33243 |
| Hexadecimal (base 16) | 36A3 |
| Base 3 | 201012001 |
| As time | 13987 seconds = 3 h 53 min 7 s |
Is 13987 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | 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 1) | 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 3) | 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 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 13987 a prime number?
No. 13987 = 71 × 197, so it is divisible by 71.
What are the factors of 13987?
1, 71, 197, 13987.
What is 13987 in binary?
11011010100011 (hexadecimal 36A3, octal 33243).
What is the square root of 13987?
About 118.2666.
Is 13987 divisible by 3?
No. Its digits add up to 28, which is not a multiple of 3.
What is special about the number 13987?
13987 is a semiprime: 71 × 197, the product of two primes.