The number 15987
15987 is a composite number with 6 divisors. Its prime factorisation is 3 Ć . Divisors (6): 1, 3, 73, 219, 5329, 15987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
15987 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
15987 is composite. Its prime factorisation is
- 3
The divisors add up to 21612; without 15987 itself that is 5625, so 15987 is deficient (5625 is less than 15987). Euler's totient Ļ(15987) = 10512 numbers up to 15987 share no factor with it.
- 4
The digits of 15987 add up to 30, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 84 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15987 = 3 \times 73^{2} \]15987 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 21612 |
| Euler totient Ļ(n) | 10512 |
| Square | 255584169 |
| Cube | 4086024109803 |
| Square root | 126.439709 (= 73ā3) |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 84 |
| Scientific notation | 1.5987 Ć |
15987 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand nine hundred and eighty-seven |
| Binary (base 2) | 11111001110011 |
| Octal (base 8) | 37163 |
| Hexadecimal (base 16) | 3E73 |
| Base 3 | 210221010 |
| As time | 15987 seconds = 4 h 26 min 27 s |
Is 15987 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 | Yes (15987 Ć· 3 = 5329) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 3) | 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 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 15987 a prime number?
No. 15987 = 3 Ć , so it is divisible by 3.
What are the factors of 15987?
1, 3, 73, 219, 5329, 15987.
What is 15987 in binary?
11111001110011 (hexadecimal 3E73, octal 37163).
What is the square root of 15987?
About 126.4397, exactly 73ā3.
Is 15987 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 15987?
It is a composite number with 6 divisors.