The number 87131
87131 is a composite number with 6 divisors. Its prime factorisation is 11 Ć . Divisors (6): 1, 11, 89, 979, 7921, 87131.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
87131 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
87131 is composite. Its prime factorisation is
- 3
The divisors add up to 96132; without 87131 itself that is 9001, so 87131 is deficient (9001 is less than 87131). Euler's totient Ļ(87131) = 78320 numbers up to 87131 share no factor with it.
- 4
The digits of 87131 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 195 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87131 = 11 \times 89^{2} \]87131 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 96132 |
| Euler totient Ļ(n) | 78320 |
| Square | 7591811161 |
| Cube | 661482098269091 |
| Square root | 295.179606 (= 89ā11) |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 195 |
| Scientific notation | 8.7131 Ć |
87131 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand one hundred and thirty-one |
| Binary (base 2) | 10101010001011011 |
| Octal (base 8) | 252133 |
| Hexadecimal (base 16) | 1545B |
| Base 3 | 11102112002 |
| As time | 87131 seconds = 24 h 12 min 11 s |
Is 87131 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 2) | 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 3) | 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 | Yes (87131 Ć· 11 = 7921) | 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 87131 a prime number?
No. 87131 = 11 Ć , so it is divisible by 11.
What are the factors of 87131?
1, 11, 89, 979, 7921, 87131.
What is 87131 in binary?
10101010001011011 (hexadecimal 1545B, octal 252133).
What is the square root of 87131?
About 295.1796, exactly 89ā11.
Is 87131 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 87131?
It is a composite number with 6 divisors.