The number 39987
39987 is a composite number with 8 divisors. Its prime factorisation is × 1481. Divisors (8): 1, 3, 9, 27, 1481, 4443, 13329, 39987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
39987 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
39987 is composite. Its prime factorisation is
- 3
The divisors add up to 59280; without 39987 itself that is 19293, so 39987 is deficient (19293 is less than 39987). Euler's totient φ(39987) = 26640 numbers up to 39987 share no factor with it.
- 4
The digits of 39987 add up to 36, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 67 steps to reach 1.
LaTeX source of the formulas on this page
\[ 39987 = 3^{3} \times 1481 \]39987 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 59280 |
| Euler totient φ(n) | 26640 |
| Square | 1598960169 |
| Cube | 63937620277803 |
| Square root | 199.967497 (= 3√4443) |
| Digit sum / digital root | 36 / 9 |
| Collatz steps to 1 | 67 |
| Scientific notation | 3.9987 × |
39987 in other forms
| Form | Value |
|---|---|
| In words | thirty-nine thousand nine hundred and eighty-seven |
| Binary (base 2) | 1001110000110011 |
| Octal (base 8) | 116063 |
| Hexadecimal (base 16) | 9C33 |
| Base 3 | 2000212000 |
| As time | 39987 seconds = 11 h 6 min 27 s |
Is 39987 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 (39987 ÷ 3 = 13329) | 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 3) | 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 (39987 ÷ 9 = 4443) | 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 2) | 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 39987 a prime number?
No. 39987 = × 1481, so it is divisible by 3.
What are the factors of 39987?
1, 3, 9, 27, 1481, 4443, 13329, 39987.
What is 39987 in binary?
1001110000110011 (hexadecimal 9C33, octal 116063).
What is the square root of 39987?
About 199.9675, exactly 3√4443.
Is 39987 divisible by 3?
Yes. Its digits add up to 36, a multiple of 3.
What is special about the number 39987?
It is a composite number with 8 divisors.