The number 20018
20018 is a composite number with 4 divisors. Its prime factorisation is 2 × 10009. Divisors (4): 1, 2, 10009, 20018.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20018: a semiprime: 2 × 10009, the product of two primes.
- 2
20018 is composite. Its prime factorisation is
- 3
The divisors add up to 30030; without 20018 itself that is 10012, so 20018 is deficient (10012 is less than 20018). Euler's totient φ(20018) = 10008 numbers up to 20018 share no factor with it.
- 4
The digits of 20018 add up to 11, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 167 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20018 = 2 \times 10009 \]
20018 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 30030 |
| Euler totient φ(n) | 10008 |
| Square | 400720324 |
| Cube | 8021619445832 |
| Square root | 141.484982 |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 167 |
| Scientific notation | 2.0018 × |
20018 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand and eighteen |
| Binary (base 2) | 100111000110010 |
| Octal (base 8) | 47062 |
| Hexadecimal (base 16) | 4E32 |
| Base 3 | 1000110102 |
| As time | 20018 seconds = 5 h 33 min 38 s |
Is 20018 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (20018 ÷ 2 = 10009) | 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 2) | 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 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 2) | 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 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20018 a prime number?
No. 20018 = 2 × 10009, so it is divisible by 2.
What are the factors of 20018?
1, 2, 10009, 20018.
What is 20018 in binary?
100111000110010 (hexadecimal 4E32, octal 47062).
What is the square root of 20018?
About 141.4850.
Is 20018 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 20018?
20018 is a semiprime: 2 × 10009, the product of two primes.