The number 18523
18523 is a twin prime (18521 and 18523 are both prime) and the 2122nd prime number. Its only divisors are 1 and 18523.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18523: a twin prime (18521 and 18523 are both prime); the 2122nd prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18523 is prime, so its only factors are 1 and 18523. It is the 2122nd prime; the next prime is 18539 and the one before is 18521.
- 3
The divisors add up to 18524; without 18523 itself that is 1, so 18523 is deficient (1 is less than 18523). Euler's totient φ(18523) = 18522 numbers up to 18523 share no factor with it.
- 4
The digits of 18523 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 141 steps to reach 1.
18523 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 18524 |
| Euler totient φ(n) | 18522 |
| Square | 343101529 |
| Cube | 6355269621667 |
| Square root | 136.099229 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 141 |
| Scientific notation | 1.8523 × |
18523 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand five hundred and twenty-three |
| Binary (base 2) | 100100001011011 |
| Octal (base 8) | 44133 |
| Hexadecimal (base 16) | 485B |
| Base 3 | 221102001 |
| As time | 18523 seconds = 5 h 8 min 43 s |
Is 18523 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 1) | 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 1) | 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 1) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18523 a prime number?
Yes. 18523 is divisible only by 1 and itself.
What are the factors of 18523?
1, 18523.
What is 18523 in binary?
100100001011011 (hexadecimal 485B, octal 44133).
What is the square root of 18523?
About 136.0992.
Is 18523 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 18523?
18523 is a twin prime (18521 and 18523 are both prime); the 2122nd prime number; a happy number: repeatedly adding the squares of its digits reaches 1.