The number 87123
87123 is a composite number with 8 divisors. Its prime factorisation is 3 × 113 × 257. Divisors (8): 1, 3, 113, 257, 339, 771, 29041, 87123.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
87123 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
87123 is composite. Its prime factorisation is
- 3
The divisors add up to 117648; without 87123 itself that is 30525, so 87123 is deficient (30525 is less than 87123). Euler's totient φ(87123) = 57344 numbers up to 87123 share no factor with it.
- 4
The digits of 87123 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 177 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87123 = 3 \times 113 \times 257 \]
87123 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 117648 |
| Euler totient φ(n) | 57344 |
| Square | 7590417129 |
| Cube | 661299911529867 |
| Square root | 295.166055 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 177 |
| Scientific notation | 8.7123 × |
87123 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand one hundred and twenty-three |
| Binary (base 2) | 10101010001010011 |
| Octal (base 8) | 252123 |
| Hexadecimal (base 16) | 15453 |
| Base 3 | 11102111210 |
| As time | 87123 seconds = 24 h 12 min 3 s |
Is 87123 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 | Yes (87123 ÷ 3 = 29041) | 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 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | 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 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 87123 a prime number?
No. 87123 = 3 × 113 × 257, so it is divisible by 3.
What are the factors of 87123?
1, 3, 113, 257, 339, 771, 29041, 87123.
What is 87123 in binary?
10101010001010011 (hexadecimal 15453, octal 252123).
What is the square root of 87123?
About 295.1661.
Is 87123 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 87123?
It is a composite number with 8 divisors.