The number 21329
21329 is a composite number with 8 divisors. Its prime factorisation is 7 × 11 × 277. Divisors (8): 1, 7, 11, 77, 277, 1939, 3047, 21329.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21329 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21329 is composite. Its prime factorisation is
- 3
The divisors add up to 26688; without 21329 itself that is 5359, so 21329 is deficient (5359 is less than 21329). Euler's totient φ(21329) = 16560 numbers up to 21329 share no factor with it.
- 4
The digits of 21329 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 193 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21329 = 7 \times 11 \times 277 \]
21329 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 26688 |
| Euler totient φ(n) | 16560 |
| Square | 454926241 |
| Cube | 9703121794289 |
| Square root | 146.044514 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 193 |
| Scientific notation | 2.1329 × |
21329 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand three hundred and twenty-nine |
| Binary (base 2) | 101001101010001 |
| Octal (base 8) | 51521 |
| Hexadecimal (base 16) | 5351 |
| Base 3 | 1002020222 |
| As time | 21329 seconds = 5 h 55 min 29 s |
Is 21329 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 1) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21329 ÷ 7 = 3047) | 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 1) | 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 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (21329 ÷ 11 = 1939) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21329 a prime number?
No. 21329 = 7 × 11 × 277, so it is divisible by 7.
What are the factors of 21329?
1, 7, 11, 77, 277, 1939, 3047, 21329.
What is 21329 in binary?
101001101010001 (hexadecimal 5351, octal 51521).
What is the square root of 21329?
About 146.0445.
Is 21329 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21329?
It is a composite number with 8 divisors.