The number 21716
21716 is a composite number with 12 divisors. Its prime factorisation is × 61 × 89. Divisors (12): 1, 2, 4, 61, 89, 122, 178, 244, 356, 5429, 10858, 21716.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21716: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
21716 is composite. Its prime factorisation is
- 3
The divisors add up to 39060; without 21716 itself that is 17344, so 21716 is deficient (17344 is less than 21716). Euler's totient φ(21716) = 10560 numbers up to 21716 share no factor with it.
- 4
The digits of 21716 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21716 = 2^{2} \times 61 \times 89 \]21716 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 39060 |
| Euler totient φ(n) | 10560 |
| Square | 471584656 |
| Cube | 10240932389696 |
| Square root | 147.363496 (= 2√5429) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1716 × |
21716 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand seven hundred and sixteen |
| Binary (base 2) | 101010011010100 |
| Octal (base 8) | 52324 |
| Hexadecimal (base 16) | 54D4 |
| Base 3 | 1002210022 |
| As time | 21716 seconds = 6 h 1 min 56 s |
Is 21716 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21716 ÷ 2 = 10858) | 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 (21716 ÷ 4 = 5429) | 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 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 6) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | 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 21716 a prime number?
No. 21716 = × 61 × 89, so it is divisible by 2.
What are the factors of 21716?
1, 2, 4, 61, 89, 122, 178, 244, 356, 5429, 10858, 21716.
What is 21716 in binary?
101010011010100 (hexadecimal 54D4, octal 52324).
What is the square root of 21716?
About 147.3635, exactly 2√5429.
Is 21716 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21716?
21716 is a happy number: repeatedly adding the squares of its digits reaches 1.