The number 21429
21429 is a composite number with 6 divisors. Its prime factorisation is × 2381. Divisors (6): 1, 3, 9, 2381, 7143, 21429.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21429 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21429 is composite. Its prime factorisation is
- 3
The divisors add up to 30966; without 21429 itself that is 9537, so 21429 is deficient (9537 is less than 21429). Euler's totient φ(21429) = 14280 numbers up to 21429 share no factor with it.
- 4
The digits of 21429 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 30 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21429 = 3^{2} \times 2381 \]21429 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 30966 |
| Euler totient φ(n) | 14280 |
| Square | 459202041 |
| Cube | 9840240536589 |
| Square root | 146.386475 (= 3√2381) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 30 |
| Scientific notation | 2.1429 × |
21429 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and twenty-nine |
| Binary (base 2) | 101001110110101 |
| Octal (base 8) | 51665 |
| Hexadecimal (base 16) | 53B5 |
| Base 3 | 1002101200 |
| As time | 21429 seconds = 5 h 57 min 9 s |
Is 21429 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 | Yes (21429 ÷ 3 = 7143) | 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 3) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (21429 ÷ 9 = 2381) | 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 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21429 a prime number?
No. 21429 = × 2381, so it is divisible by 3.
What are the factors of 21429?
1, 3, 9, 2381, 7143, 21429.
What is 21429 in binary?
101001110110101 (hexadecimal 53B5, octal 51665).
What is the square root of 21429?
About 146.3865, exactly 3√2381.
Is 21429 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 21429?
It is a composite number with 6 divisors.