The number 21764
21764 is a composite number with 6 divisors. Its prime factorisation is × 5441. Divisors (6): 1, 2, 4, 5441, 10882, 21764.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21764 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21764 is composite. Its prime factorisation is
- 3
The divisors add up to 38094; without 21764 itself that is 16330, so 21764 is deficient (16330 is less than 21764). Euler's totient φ(21764) = 10880 numbers up to 21764 share no factor with it.
- 4
The digits of 21764 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21764 = 2^{2} \times 5441 \]21764 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 38094 |
| Euler totient φ(n) | 10880 |
| Square | 473671696 |
| Cube | 10308990791744 |
| Square root | 147.526269 (= 2√5441) |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1764 × |
21764 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand seven hundred and sixty-four |
| Binary (base 2) | 101010100000100 |
| Octal (base 8) | 52404 |
| Hexadecimal (base 16) | 5504 |
| Base 3 | 1002212002 |
| As time | 21764 seconds = 6 h 2 min 44 s |
Is 21764 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21764 ÷ 2 = 10882) | 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 (21764 ÷ 4 = 5441) | 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 1) | 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 2) | 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 6) | 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 21764 a prime number?
No. 21764 = × 5441, so it is divisible by 2.
What are the factors of 21764?
1, 2, 4, 5441, 10882, 21764.
What is 21764 in binary?
101010100000100 (hexadecimal 5504, octal 52404).
What is the square root of 21764?
About 147.5263, exactly 2√5441.
Is 21764 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 21764?
It is a composite number with 6 divisors.