The number 9987
9987 is a composite number with 4 divisors. Its prime factorisation is 3 × 3329. Divisors (4): 1, 3, 3329, 9987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 9987: a semiprime: 3 × 3329, the product of two primes.
- 2
9987 is composite. Its prime factorisation is
- 3
The divisors add up to 13320; without 9987 itself that is 3333, so 9987 is deficient (3333 is less than 9987). Euler's totient φ(9987) = 6656 numbers up to 9987 share no factor with it.
- 4
The digits of 9987 add up to 33, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 166 steps to reach 1.
LaTeX source of the formulas on this page
\[ 9987 = 3 \times 3329 \]
9987 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 13320 |
| Euler totient φ(n) | 6656 |
| Square | 99740169 |
| Cube | 996105067803 |
| Square root | 99.934979 |
| Digit sum / digital root | 33 / 6 |
| Collatz steps to 1 | 166 |
| Scientific notation | 9.987 × |
9987 in other forms
| Form | Value |
|---|---|
| In words | nine thousand nine hundred and eighty-seven |
| Binary (base 2) | 10011100000011 |
| Octal (base 8) | 23403 |
| Hexadecimal (base 16) | 2703 |
| Base 3 | 111200220 |
| As time | 9987 seconds = 2 h 46 min 27 s |
Is 9987 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 (9987 ÷ 3 = 3329) | 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 5) | 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 6) | 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 10) | 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 9987 a prime number?
No. 9987 = 3 × 3329, so it is divisible by 3.
What are the factors of 9987?
1, 3, 3329, 9987.
What is 9987 in binary?
10011100000011 (hexadecimal 2703, octal 23403).
What is the square root of 9987?
About 99.9350.
Is 9987 divisible by 3?
Yes. Its digits add up to 33, a multiple of 3.
What is special about the number 9987?
9987 is a semiprime: 3 × 3329, the product of two primes.