The number 21704
21704 is a composite number with 8 divisors. Its prime factorisation is × 2713. Divisors (8): 1, 2, 4, 8, 2713, 5426, 10852, 21704.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21704: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
21704 is composite. Its prime factorisation is
- 3
The divisors add up to 40710; without 21704 itself that is 19006, so 21704 is deficient (19006 is less than 21704). Euler's totient φ(21704) = 10848 numbers up to 21704 share no factor with it.
- 4
The digits of 21704 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 162 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21704 = 2^{3} \times 2713 \]21704 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 40710 |
| Euler totient φ(n) | 10848 |
| Square | 471063616 |
| Cube | 10223964721664 |
| Square root | 147.322775 (= 2√5426) |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 162 |
| Scientific notation | 2.1704 × |
21704 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand seven hundred and four |
| Binary (base 2) | 101010011001000 |
| Octal (base 8) | 52310 |
| Hexadecimal (base 16) | 54C8 |
| Base 3 | 1002202212 |
| As time | 21704 seconds = 6 h 1 min 44 s |
Is 21704 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21704 ÷ 2 = 10852) | 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 | Yes (21704 ÷ 4 = 5426) | 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 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 (21704 ÷ 8 = 2713) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21704 a prime number?
No. 21704 = × 2713, so it is divisible by 2.
What are the factors of 21704?
1, 2, 4, 8, 2713, 5426, 10852, 21704.
What is 21704 in binary?
101010011001000 (hexadecimal 54C8, octal 52310).
What is the square root of 21704?
About 147.3228, exactly 2√5426.
Is 21704 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 21704?
21704 is a happy number: repeatedly adding the squares of its digits reaches 1.