The number 20711
20711 is a composite number with 4 divisors. Its prime factorisation is 139 × 149. Divisors (4): 1, 139, 149, 20711.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20711: a semiprime: 139 × 149, the product of two primes.
- 2
20711 is composite. Its prime factorisation is
- 3
The divisors add up to 21000; without 20711 itself that is 289, so 20711 is deficient (289 is less than 20711). Euler's totient φ(20711) = 20424 numbers up to 20711 share no factor with it.
- 4
The digits of 20711 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 61 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20711 = 139 \times 149 \]
20711 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 21000 |
| Euler totient φ(n) | 20424 |
| Square | 428945521 |
| Cube | 8883890685431 |
| Square root | 143.913168 |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 61 |
| Scientific notation | 2.0711 × |
20711 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand seven hundred and eleven |
| Binary (base 2) | 101000011100111 |
| Octal (base 8) | 50347 |
| Hexadecimal (base 16) | 50E7 |
| Base 3 | 1001102002 |
| As time | 20711 seconds = 5 h 45 min 11 s |
Is 20711 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | 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 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 7) | 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 1) | 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 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20711 a prime number?
No. 20711 = 139 × 149, so it is divisible by 139.
What are the factors of 20711?
1, 139, 149, 20711.
What is 20711 in binary?
101000011100111 (hexadecimal 50E7, octal 50347).
What is the square root of 20711?
About 143.9132.
Is 20711 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 20711?
20711 is a semiprime: 139 × 149, the product of two primes.