The number 18787
18787 is the 2143rd prime number. Its only divisors are 1 and 18787.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18787: the 2143rd prime number.
- 2
18787 is prime, so its only factors are 1 and 18787. It is the 2143rd prime; the next prime is 18793 and the one before is 18773.
- 3
The divisors add up to 18788; without 18787 itself that is 1, so 18787 is deficient (1 is less than 18787). Euler's totient φ(18787) = 18786 numbers up to 18787 share no factor with it.
- 4
The digits of 18787 add up to 31, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 110 steps to reach 1.
18787 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 18788 |
| Euler totient φ(n) | 18786 |
| Square | 352951369 |
| Cube | 6630897369403 |
| Square root | 137.065678 |
| Digit sum / digital root | 31 / 4 |
| Collatz steps to 1 | 110 |
| Scientific notation | 1.8787 × |
18787 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand seven hundred and eighty-seven |
| Binary (base 2) | 100100101100011 |
| Octal (base 8) | 44543 |
| Hexadecimal (base 16) | 4963 |
| Base 3 | 221202211 |
| As time | 18787 seconds = 5 h 13 min 7 s |
Is 18787 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 1) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 4) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18787 a prime number?
Yes. 18787 is divisible only by 1 and itself.
What are the factors of 18787?
1, 18787.
What is 18787 in binary?
100100101100011 (hexadecimal 4963, octal 44543).
What is the square root of 18787?
About 137.0657.
Is 18787 divisible by 3?
No. Its digits add up to 31, which is not a multiple of 3.
What is special about the number 18787?
18787 is the 2143rd prime number.