The number 67991
67991 is a composite number with 8 divisors. Its prime factorisation is 7 × 11 × 883. Divisors (8): 1, 7, 11, 77, 883, 6181, 9713, 67991.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
67991 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
67991 is composite. Its prime factorisation is
- 3
The divisors add up to 84864; without 67991 itself that is 16873, so 67991 is deficient (16873 is less than 67991). Euler's totient φ(67991) = 52920 numbers up to 67991 share no factor with it.
- 4
The digits of 67991 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 86 steps to reach 1.
LaTeX source of the formulas on this page
\[ 67991 = 7 \times 11 \times 883 \]
67991 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 84864 |
| Euler totient φ(n) | 52920 |
| Square | 4622776081 |
| Cube | 314307168523271 |
| Square root | 260.750839 |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 86 |
| Scientific notation | 6.7991 × |
67991 in other forms
| Form | Value |
|---|---|
| In words | sixty-seven thousand nine hundred and ninety-one |
| Binary (base 2) | 10000100110010111 |
| Octal (base 8) | 204627 |
| Hexadecimal (base 16) | 10997 |
| Base 3 | 10110021012 |
| As time | 67991 seconds = 18 h 53 min 11 s |
Is 67991 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 | Yes (67991 ÷ 7 = 9713) | 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 | Yes (67991 ÷ 11 = 6181) | 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 67991 a prime number?
No. 67991 = 7 × 11 × 883, so it is divisible by 7.
What are the factors of 67991?
1, 7, 11, 77, 883, 6181, 9713, 67991.
What is 67991 in binary?
10000100110010111 (hexadecimal 10997, octal 204627).
What is the square root of 67991?
About 260.7508.
Is 67991 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 67991?
It is a composite number with 8 divisors.