The number 17987
17987 is a twin prime (17987 and 17989 are both prime) and the 2063rd prime number. Its only divisors are 1 and 17987.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 17987: a twin prime (17987 and 17989 are both prime); the 2063rd prime number.
- 2
17987 is prime, so its only factors are 1 and 17987. It is the 2063rd prime; the next prime is 17989 and the one before is 17981.
- 3
The divisors add up to 17988; without 17987 itself that is 1, so 17987 is deficient (1 is less than 17987). Euler's totient φ(17987) = 17986 numbers up to 17987 share no factor with it.
- 4
The digits of 17987 add up to 32, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 79 steps to reach 1.
17987 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 17988 |
| Euler totient φ(n) | 17986 |
| Square | 323532169 |
| Cube | 5819373123803 |
| Square root | 134.115622 |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 79 |
| Scientific notation | 1.7987 × |
17987 in other forms
| Form | Value |
|---|---|
| In words | seventeen thousand nine hundred and eighty-seven |
| Binary (base 2) | 100011001000011 |
| Octal (base 8) | 43103 |
| Hexadecimal (base 16) | 4643 |
| Base 3 | 220200012 |
| As time | 17987 seconds = 4 h 59 min 47 s |
Is 17987 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 | No (remainder 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 5) | 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 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 17987 a prime number?
Yes. 17987 is divisible only by 1 and itself.
What are the factors of 17987?
1, 17987.
What is 17987 in binary?
100011001000011 (hexadecimal 4643, octal 43103).
What is the square root of 17987?
About 134.1156.
Is 17987 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 17987?
17987 is a twin prime (17987 and 17989 are both prime); the 2063rd prime number.