The number 21712
21712 is a palindrome: it reads 21712 backwards too. Its prime factorisation is × 23 × 59. Divisors (20): 1, 2, 4, 8, 16, 23, 46, 59, 92, 118, 184, 236, 368, 472, 944, 1357 … 21712.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21712: a palindrome: it reads 21712 backwards too.
- 2
21712 is composite. Its prime factorisation is
- 3
The divisors add up to 44640; without 21712 itself that is 22928, so 21712 is abundant (22928 is more than 21712). Euler's totient φ(21712) = 10208 numbers up to 21712 share no factor with it.
- 4
The digits of 21712 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21712 = 2^{4} \times 23 \times 59 \]21712 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 44640 |
| Euler totient φ(n) | 10208 |
| Square | 471410944 |
| Cube | 10235274416128 |
| Square root | 147.349924 (= 4√1357) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1712 × |
21712 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand seven hundred and twelve |
| Binary (base 2) | 101010011010000 |
| Octal (base 8) | 52320 |
| Hexadecimal (base 16) | 54D0 |
| Base 3 | 1002210011 |
| As time | 21712 seconds = 6 h 1 min 52 s |
Is 21712 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21712 ÷ 2 = 10856) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21712 ÷ 4 = 5428) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 | Yes (21712 ÷ 8 = 2714) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | 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 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21712 a prime number?
No. 21712 = × 23 × 59, so it is divisible by 2.
What are the factors of 21712?
1, 2, 4, 8, 16, 23, 46, 59, 92, 118, 184, 236, 368, 472, 944, 1357, 2714, 5428, 10856, 21712.
What is 21712 in binary?
101010011010000 (hexadecimal 54D0, octal 52320).
What is the square root of 21712?
About 147.3499, exactly 4√1357.
Is 21712 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 21712?
21712 is a palindrome: it reads 21712 backwards too.