The number 21425
21425 is a composite number with 6 divisors. Its prime factorisation is Ć 857. Divisors (6): 1, 5, 25, 857, 4285, 21425.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21425 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21425 is composite. Its prime factorisation is
- 3
The divisors add up to 26598; without 21425 itself that is 5173, so 21425 is deficient (5173 is less than 21425). Euler's totient Ļ(21425) = 17120 numbers up to 21425 share no factor with it.
- 4
The digits of 21425 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 30 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21425 = 5^{2} \times 857 \]21425 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 26598 |
| Euler totient Ļ(n) | 17120 |
| Square | 459030625 |
| Cube | 9834731140625 |
| Square root | 146.372812 (= 5ā857) |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 30 |
| Scientific notation | 2.1425 Ć |
21425 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and twenty-five |
| Binary (base 2) | 101001110110001 |
| Octal (base 8) | 51661 |
| Hexadecimal (base 16) | 53B1 |
| Base 3 | 1002101112 |
| As time | 21425 seconds = 5 h 57 min 5 s |
Is 21425 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 | Yes (21425 Ć· 5 = 4285) | 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 | No (remainder 5) | 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 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | 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 21425 a prime number?
No. 21425 = Ć 857, so it is divisible by 5.
What are the factors of 21425?
1, 5, 25, 857, 4285, 21425.
What is 21425 in binary?
101001110110001 (hexadecimal 53B1, octal 51661).
What is the square root of 21425?
About 146.3728, exactly 5ā857.
Is 21425 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 21425?
It is a composite number with 6 divisors.