The number 87311
87311 is a composite number with 4 divisors. Its prime factorisation is 7 × 12473. Divisors (4): 1, 7, 12473, 87311.
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How to work it out
- 1
What is special about 87311: a semiprime: 7 × 12473, the product of two primes.
- 2
87311 is composite. Its prime factorisation is
- 3
The divisors add up to 99792; without 87311 itself that is 12481, so 87311 is deficient (12481 is less than 87311). Euler's totient φ(87311) = 74832 numbers up to 87311 share no factor with it.
- 4
The digits of 87311 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 58 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87311 = 7 \times 12473 \]
87311 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 99792 |
| Euler totient φ(n) | 74832 |
| Square | 7623210721 |
| Cube | 665590151261231 |
| Square root | 295.484348 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 58 |
| Scientific notation | 8.7311 × |
87311 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand three hundred and eleven |
| Binary (base 2) | 10101010100001111 |
| Octal (base 8) | 252417 |
| Hexadecimal (base 16) | 1550F |
| Base 3 | 11102202202 |
| As time | 87311 seconds = 24 h 15 min 11 s |
Is 87311 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 (87311 ÷ 7 = 12473) | 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 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 87311 a prime number?
No. 87311 = 7 × 12473, so it is divisible by 7.
What are the factors of 87311?
1, 7, 12473, 87311.
What is 87311 in binary?
10101010100001111 (hexadecimal 1550F, octal 252417).
What is the square root of 87311?
About 295.4843.
Is 87311 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 87311?
87311 is a semiprime: 7 × 12473, the product of two primes.