The number 42787
42787 is the 4474th prime number. Its only divisors are 1 and 42787.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42787: the 4474th prime number.
- 2
42787 is prime, so its only factors are 1 and 42787. It is the 4474th prime; the next prime is 42793 and the one before is 42773.
- 3
The divisors add up to 42788; without 42787 itself that is 1, so 42787 is deficient (1 is less than 42787). Euler's totient φ(42787) = 42786 numbers up to 42787 share no factor with it.
- 4
The digits of 42787 add up to 28, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 194 steps to reach 1.
42787 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 42788 |
| Euler totient φ(n) | 42786 |
| Square | 1830727369 |
| Cube | 78331331937403 |
| Square root | 206.850187 |
| Digit sum / digital root | 28 / 1 |
| Collatz steps to 1 | 194 |
| Scientific notation | 4.2787 × |
42787 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand seven hundred and eighty-seven |
| Binary (base 2) | 1010011100100011 |
| Octal (base 8) | 123443 |
| Hexadecimal (base 16) | A723 |
| Base 3 | 2011200201 |
| As time | 42787 seconds = 11 h 53 min 7 s |
Is 42787 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 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 | No (remainder 1) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42787 a prime number?
Yes. 42787 is divisible only by 1 and itself.
What are the factors of 42787?
1, 42787.
What is 42787 in binary?
1010011100100011 (hexadecimal A723, octal 123443).
What is the square root of 42787?
About 206.8502.
Is 42787 divisible by 3?
No. Its digits add up to 28, which is not a multiple of 3.
What is special about the number 42787?
42787 is the 4474th prime number.