The number 25409
25409 is a twin prime (25409 and 25411 are both prime) and the 2801st prime number. Its only divisors are 1 and 25409.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 25409: a twin prime (25409 and 25411 are both prime); the 2801st prime number.
- 2
25409 is prime, so its only factors are 1 and 25409. It is the 2801st prime; the next prime is 25411 and the one before is 25391.
- 3
The divisors add up to 25410; without 25409 itself that is 1, so 25409 is deficient (1 is less than 25409). Euler's totient φ(25409) = 25408 numbers up to 25409 share no factor with it.
- 4
The digits of 25409 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 82 steps to reach 1.
25409 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 25410 |
| Euler totient φ(n) | 25408 |
| Square | 645617281 |
| Cube | 16404489492929 |
| Square root | 159.402008 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 82 |
| Scientific notation | 2.5409 × |
25409 in other forms
| Form | Value |
|---|---|
| In words | twenty-five thousand four hundred and nine |
| Binary (base 2) | 110001101000001 |
| Octal (base 8) | 61501 |
| Hexadecimal (base 16) | 6341 |
| Base 3 | 1021212002 |
| As time | 25409 seconds = 7 h 3 min 29 s |
Is 25409 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 | No (remainder 6) | 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 2) | 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 10) | 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 25409 a prime number?
Yes. 25409 is divisible only by 1 and itself.
What are the factors of 25409?
1, 25409.
What is 25409 in binary?
110001101000001 (hexadecimal 6341, octal 61501).
What is the square root of 25409?
About 159.4020.
Is 25409 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 25409?
25409 is a twin prime (25409 and 25411 are both prime); the 2801st prime number.