The number 12987
12987 is a composite number with 16 divisors. Its prime factorisation is × 13 × 37. Divisors (16): 1, 3, 9, 13, 27, 37, 39, 111, 117, 333, 351, 481, 999, 1443, 4329, 12987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 12987: a Harshad number: divisible by its digit sum 27.
- 2
12987 is composite. Its prime factorisation is
- 3
The divisors add up to 21280; without 12987 itself that is 8293, so 12987 is deficient (8293 is less than 12987). Euler's totient φ(12987) = 7776 numbers up to 12987 share no factor with it.
- 4
The digits of 12987 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 200 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12987 = 3^{3} \times 13 \times 37 \]12987 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 21280 |
| Euler totient φ(n) | 7776 |
| Square | 168662169 |
| Cube | 2190415588803 |
| Square root | 113.960519 (= 3√1443) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 200 |
| Scientific notation | 1.2987 × |
12987 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand nine hundred and eighty-seven |
| Binary (base 2) | 11001010111011 |
| Octal (base 8) | 31273 |
| Hexadecimal (base 16) | 32BB |
| Base 3 | 122211000 |
| As time | 12987 seconds = 3 h 36 min 27 s |
Is 12987 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 (12987 ÷ 3 = 4329) | 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 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (12987 ÷ 9 = 1443) | 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 7) | 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 12987 a prime number?
No. 12987 = × 13 × 37, so it is divisible by 3.
What are the factors of 12987?
1, 3, 9, 13, 27, 37, 39, 111, 117, 333, 351, 481, 999, 1443, 4329, 12987.
What is 12987 in binary?
11001010111011 (hexadecimal 32BB, octal 31273).
What is the square root of 12987?
About 113.9605, exactly 3√1443.
Is 12987 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 12987?
12987 is a Harshad number: divisible by its digit sum 27.