The number 18123
18123 is a composite number with 8 divisors. Its prime factorisation is 3 × 7 × 863. Divisors (8): 1, 3, 7, 21, 863, 2589, 6041, 18123.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18123: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18123 is composite. Its prime factorisation is
- 3
The divisors add up to 27648; without 18123 itself that is 9525, so 18123 is deficient (9525 is less than 18123). Euler's totient φ(18123) = 10344 numbers up to 18123 share no factor with it.
- 4
The digits of 18123 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 185 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18123 = 3 \times 7 \times 863 \]
18123 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 27648 |
| Euler totient φ(n) | 10344 |
| Square | 328443129 |
| Cube | 5952374826867 |
| Square root | 134.621692 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 185 |
| Scientific notation | 1.8123 × |
18123 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand one hundred and twenty-three |
| Binary (base 2) | 100011011001011 |
| Octal (base 8) | 43313 |
| Hexadecimal (base 16) | 46CB |
| Base 3 | 220212020 |
| As time | 18123 seconds = 5 h 2 min 3 s |
Is 18123 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 (18123 ÷ 3 = 6041) | 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 | Yes (18123 ÷ 7 = 2589) | 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 6) | 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 6) | 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 18123 a prime number?
No. 18123 = 3 × 7 × 863, so it is divisible by 3.
What are the factors of 18123?
1, 3, 7, 21, 863, 2589, 6041, 18123.
What is 18123 in binary?
100011011001011 (hexadecimal 46CB, octal 43313).
What is the square root of 18123?
About 134.6217.
Is 18123 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 18123?
18123 is a happy number: repeatedly adding the squares of its digits reaches 1.