The number 25421
25421 is a composite number with 4 divisors. Its prime factorisation is 11 × 2311. Divisors (4): 1, 11, 2311, 25421.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 25421: a semiprime: 11 × 2311, the product of two primes.
- 2
25421 is composite. Its prime factorisation is
- 3
The divisors add up to 27744; without 25421 itself that is 2323, so 25421 is deficient (2323 is less than 25421). Euler's totient φ(25421) = 23100 numbers up to 25421 share no factor with it.
- 4
The digits of 25421 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 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 25421 = 11 \times 2311 \]
25421 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 27744 |
| Euler totient φ(n) | 23100 |
| Square | 646227241 |
| Cube | 16427742693461 |
| Square root | 159.439644 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.5421 × |
25421 in other forms
| Form | Value |
|---|---|
| In words | twenty-five thousand four hundred and twenty-one |
| Binary (base 2) | 110001101001101 |
| Octal (base 8) | 61515 |
| Hexadecimal (base 16) | 634D |
| Base 3 | 1021212112 |
| As time | 25421 seconds = 7 h 3 min 41 s |
Is 25421 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 1) | 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 4) | 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 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (25421 ÷ 11 = 2311) | 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 25421 a prime number?
No. 25421 = 11 × 2311, so it is divisible by 11.
What are the factors of 25421?
1, 11, 2311, 25421.
What is 25421 in binary?
110001101001101 (hexadecimal 634D, octal 61515).
What is the square root of 25421?
About 159.4396.
Is 25421 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 25421?
25421 is a semiprime: 11 × 2311, the product of two primes.