The number 78887
78887 is a palindromic prime: it reads the same backwards and is prime, a twin prime (78887 and 78889 are both prime) and the 7737th prime number. Its only divisors are 1 and 78887.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 78887: a palindromic prime: it reads the same backwards and is prime; a twin prime (78887 and 78889 are both prime); the 7737th prime number; a palindrome: it reads 78887 backwards too.
- 2
78887 is prime, so its only factors are 1 and 78887. It is the 7737th prime; the next prime is 78889 and the one before is 78877.
- 3
The divisors add up to 78888; without 78887 itself that is 1, so 78887 is deficient (1 is less than 78887). Euler's totient φ(78887) = 78886 numbers up to 78887 share no factor with it.
- 4
The digits of 78887 add up to 38, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 63 steps to reach 1.
78887 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 78888 |
| Euler totient φ(n) | 78886 |
| Square | 6223158769 |
| Cube | 490926325810103 |
| Square root | 280.868297 |
| Digit sum / digital root | 38 / 2 |
| Collatz steps to 1 | 63 |
| Scientific notation | 7.8887 × |
78887 in other forms
| Form | Value |
|---|---|
| In words | seventy-eight thousand eight hundred and eighty-seven |
| Binary (base 2) | 10011010000100111 |
| Octal (base 8) | 232047 |
| Hexadecimal (base 16) | 13427 |
| Base 3 | 11000012202 |
| As time | 78887 seconds = 21 h 54 min 47 s |
Is 78887 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | 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 6) | 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 78887 a prime number?
Yes. 78887 is divisible only by 1 and itself.
What are the factors of 78887?
1, 78887.
What is 78887 in binary?
10011010000100111 (hexadecimal 13427, octal 232047).
What is the square root of 78887?
About 280.8683.
Is 78887 divisible by 3?
No. Its digits add up to 38, which is not a multiple of 3.
What is special about the number 78887?
78887 is a palindromic prime: it reads the same backwards and is prime; a twin prime (78887 and 78889 are both prime); the 7737th prime number; a palindrome: it reads 78887 backwards too.