The number 20009
20009 is a composite number with 8 divisors. Its prime factorisation is 11 × 17 × 107. Divisors (8): 1, 11, 17, 107, 187, 1177, 1819, 20009.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20009: a Harshad number: divisible by its digit sum 11.
- 2
20009 is composite. Its prime factorisation is
- 3
The divisors add up to 23328; without 20009 itself that is 3319, so 20009 is deficient (3319 is less than 20009). Euler's totient φ(20009) = 16960 numbers up to 20009 share no factor with it.
- 4
The digits of 20009 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
\[ 20009 = 11 \times 17 \times 107 \]
20009 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 23328 |
| Euler totient φ(n) | 16960 |
| Square | 400360081 |
| Cube | 8010804860729 |
| Square root | 141.453172 |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 167 |
| Scientific notation | 2.0009 × |
20009 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand and nine |
| Binary (base 2) | 100111000101001 |
| Octal (base 8) | 47051 |
| Hexadecimal (base 16) | 4E29 |
| Base 3 | 1000110002 |
| As time | 20009 seconds = 5 h 33 min 29 s |
Is 20009 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 2) | 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 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (20009 ÷ 11 = 1819) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20009 a prime number?
No. 20009 = 11 × 17 × 107, so it is divisible by 11.
What are the factors of 20009?
1, 11, 17, 107, 187, 1177, 1819, 20009.
What is 20009 in binary?
100111000101001 (hexadecimal 4E29, octal 47051).
What is the square root of 20009?
About 141.4532.
Is 20009 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 20009?
20009 is a Harshad number: divisible by its digit sum 11.