The number 97991
97991 is a composite number with 8 divisors. Its prime factorisation is 29 × 31 × 109. Divisors (8): 1, 29, 31, 109, 899, 3161, 3379, 97991.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 97991: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
97991 is composite. Its prime factorisation is
- 3
The divisors add up to 105600; without 97991 itself that is 7609, so 97991 is deficient (7609 is less than 97991). Euler's totient φ(97991) = 90720 numbers up to 97991 share no factor with it.
- 4
The digits of 97991 add up to 35, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 190 steps to reach 1.
LaTeX source of the formulas on this page
\[ 97991 = 29 \times 31 \times 109 \]
97991 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 105600 |
| Euler totient φ(n) | 90720 |
| Square | 9602236081 |
| Cube | 940932715813271 |
| Square root | 313.035142 |
| Digit sum / digital root | 35 / 8 |
| Collatz steps to 1 | 190 |
| Scientific notation | 9.7991 × |
97991 in other forms
| Form | Value |
|---|---|
| In words | ninety-seven thousand nine hundred and ninety-one |
| Binary (base 2) | 10111111011000111 |
| Octal (base 8) | 277307 |
| Hexadecimal (base 16) | 17EC7 |
| Base 3 | 11222102022 |
| As time | 97991 seconds = 27 h 13 min 11 s |
Is 97991 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 8) | 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 3) | 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 97991 a prime number?
No. 97991 = 29 × 31 × 109, so it is divisible by 29.
What are the factors of 97991?
1, 29, 31, 109, 899, 3161, 3379, 97991.
What is 97991 in binary?
10111111011000111 (hexadecimal 17EC7, octal 277307).
What is the square root of 97991?
About 313.0351.
Is 97991 divisible by 3?
No. Its digits add up to 35, which is not a multiple of 3.
What is special about the number 97991?
97991 is a happy number: repeatedly adding the squares of its digits reaches 1.