The number 18993
18993 is a composite number with 8 divisors. Its prime factorisation is 3 × 13 × 487. Divisors (8): 1, 3, 13, 39, 487, 1461, 6331, 18993.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18993: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
18993 is composite. Its prime factorisation is
- 3
The divisors add up to 27328; without 18993 itself that is 8335, so 18993 is deficient (8335 is less than 18993). Euler's totient φ(18993) = 11664 numbers up to 18993 share no factor with it.
- 4
The digits of 18993 add up to 30, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 53 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18993 = 3 \times 13 \times 487 \]
18993 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 27328 |
| Euler totient φ(n) | 11664 |
| Square | 360734049 |
| Cube | 6851421792657 |
| Square root | 137.815094 |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 53 |
| Scientific notation | 1.8993 × |
18993 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand nine hundred and ninety-three |
| Binary (base 2) | 100101000110001 |
| Octal (base 8) | 45061 |
| Hexadecimal (base 16) | 4A31 |
| Base 3 | 222001110 |
| As time | 18993 seconds = 5 h 16 min 33 s |
Is 18993 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 (18993 ÷ 3 = 6331) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | 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 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 1) | 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 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18993 a prime number?
No. 18993 = 3 × 13 × 487, so it is divisible by 3.
What are the factors of 18993?
1, 3, 13, 39, 487, 1461, 6331, 18993.
What is 18993 in binary?
100101000110001 (hexadecimal 4A31, octal 45061).
What is the square root of 18993?
About 137.8151.
Is 18993 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 18993?
18993 is a happy number: repeatedly adding the squares of its digits reaches 1.