The number 987
987 is a Fibonacci number. Its prime factorisation is 3 × 7 × 47. Divisors (8): 1, 3, 7, 21, 47, 141, 329, 987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 987: a Fibonacci number.
- 2
987 is composite. Its prime factorisation is
- 3
The divisors add up to 1536; without 987 itself that is 549, so 987 is deficient (549 is less than 987). Euler's totient φ(987) = 552 numbers up to 987 share no factor with it.
- 4
The digits of 987 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 36 steps to reach 1.
LaTeX source of the formulas on this page
\[ 987 = 3 \times 7 \times 47 \]
987 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 1536 |
| Euler totient φ(n) | 552 |
| Square | 974169 |
| Cube | 961504803 |
| Square root | 31.416556 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 36 |
| Scientific notation | 9.87 × |
987 in other forms
| Form | Value |
|---|---|
| In words | nine hundred and eighty-seven |
| Roman numerals | CMLXXXVII |
| Binary (base 2) | 1111011011 |
| Octal (base 8) | 1733 |
| Hexadecimal (base 16) | 3DB |
| Base 3 | 1100120 |
| As time | 987 seconds = 16 min 27 s |
Is 987 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 (987 ÷ 3 = 329) | 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 | Yes (987 ÷ 7 = 141) | 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 8) | 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 987 a prime number?
No. 987 = 3 × 7 × 47, so it is divisible by 3.
What are the factors of 987?
1, 3, 7, 21, 47, 141, 329, 987.
What is 987 in binary?
1111011011 (hexadecimal 3DB, octal 1733).
What is the square root of 987?
About 31.4166.
What is 987 in Roman numerals?
CMLXXXVII.
Is 987 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 987?
987 is a Fibonacci number.