The number 76991
76991 is the 7567th prime number. Its only divisors are 1 and 76991.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 76991: the 7567th prime number.
- 2
76991 is prime, so its only factors are 1 and 76991. It is the 7567th prime; the next prime is 77003 and the one before is 76963.
- 3
The divisors add up to 76992; without 76991 itself that is 1, so 76991 is deficient (1 is less than 76991). Euler's totient φ(76991) = 76990 numbers up to 76991 share no factor with it.
- 4
The digits of 76991 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 187 steps to reach 1.
76991 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 76992 |
| Euler totient φ(n) | 76990 |
| Square | 5927614081 |
| Cube | 456372935710271 |
| Square root | 277.472521 |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 187 |
| Scientific notation | 7.6991 × |
76991 in other forms
| Form | Value |
|---|---|
| In words | seventy-six thousand nine hundred and ninety-one |
| Binary (base 2) | 10010110010111111 |
| Octal (base 8) | 226277 |
| Hexadecimal (base 16) | 12CBF |
| Base 3 | 10220121112 |
| As time | 76991 seconds = 21 h 23 min 11 s |
Is 76991 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 1) | 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 5) | 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 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | 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 76991 a prime number?
Yes. 76991 is divisible only by 1 and itself.
What are the factors of 76991?
1, 76991.
What is 76991 in binary?
10010110010111111 (hexadecimal 12CBF, octal 226277).
What is the square root of 76991?
About 277.4725.
Is 76991 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 76991?
76991 is the 7567th prime number.