The number 21430
21430 is a composite number with 8 divisors. Its prime factorisation is 2 × 5 × 2143. Divisors (8): 1, 2, 5, 10, 2143, 4286, 10715, 21430.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21430: a Harshad number: divisible by its digit sum 10.
- 2
21430 is composite. Its prime factorisation is
- 3
The divisors add up to 38592; without 21430 itself that is 17162, so 21430 is deficient (17162 is less than 21430). Euler's totient φ(21430) = 8568 numbers up to 21430 share no factor with it.
- 4
The digits of 21430 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 193 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21430 = 2 \times 5 \times 2143 \]
21430 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 38592 |
| Euler totient φ(n) | 8568 |
| Square | 459244900 |
| Cube | 9841618207000 |
| Square root | 146.389890 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 193 |
| Scientific notation | 2.143 × |
21430 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and thirty |
| Binary (base 2) | 101001110110110 |
| Octal (base 8) | 51666 |
| Hexadecimal (base 16) | 53B6 |
| Base 3 | 1002101201 |
| As time | 21430 seconds = 5 h 57 min 10 s |
Is 21430 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21430 ÷ 2 = 10715) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (21430 ÷ 5 = 4286) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21430 ÷ 10 = 2143) | 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 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21430 a prime number?
No. 21430 = 2 × 5 × 2143, so it is divisible by 2.
What are the factors of 21430?
1, 2, 5, 10, 2143, 4286, 10715, 21430.
What is 21430 in binary?
101001110110110 (hexadecimal 53B6, octal 51666).
What is the square root of 21430?
About 146.3899.
Is 21430 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 21430?
21430 is a Harshad number: divisible by its digit sum 10.