The number 20709
20709 is a composite number with 16 divisors. Its prime factorisation is × 13 × 59. Divisors (16): 1, 3, 9, 13, 27, 39, 59, 117, 177, 351, 531, 767, 1593, 2301, 6903, 20709.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
20709 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
20709 is composite. Its prime factorisation is
- 3
The divisors add up to 33600; without 20709 itself that is 12891, so 20709 is deficient (12891 is less than 20709). Euler's totient φ(20709) = 12528 numbers up to 20709 share no factor with it.
- 4
The digits of 20709 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20709 = 3^{3} \times 13 \times 59 \]20709 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 33600 |
| Euler totient φ(n) | 12528 |
| Square | 428862681 |
| Cube | 8881317260829 |
| Square root | 143.906219 (= 3√2301) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.0709 × |
20709 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand seven hundred and nine |
| Binary (base 2) | 101000011100101 |
| Octal (base 8) | 50345 |
| Hexadecimal (base 16) | 50E5 |
| Base 3 | 1001102000 |
| As time | 20709 seconds = 5 h 45 min 9 s |
Is 20709 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 (20709 ÷ 3 = 6903) | 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 3) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (20709 ÷ 9 = 2301) | 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 | 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 20709 a prime number?
No. 20709 = × 13 × 59, so it is divisible by 3.
What are the factors of 20709?
1, 3, 9, 13, 27, 39, 59, 117, 177, 351, 531, 767, 1593, 2301, 6903, 20709.
What is 20709 in binary?
101000011100101 (hexadecimal 50E5, octal 50345).
What is the square root of 20709?
About 143.9062, exactly 3√2301.
Is 20709 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 20709?
It is a composite number with 16 divisors.