The number 25801
25801 is a twin prime (25799 and 25801 are both prime) and the 2841st prime number. Its only divisors are 1 and 25801.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 25801: a twin prime (25799 and 25801 are both prime); the 2841st prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
25801 is prime, so its only factors are 1 and 25801. It is the 2841st prime; the next prime is 25819 and the one before is 25799.
- 3
The divisors add up to 25802; without 25801 itself that is 1, so 25801 is deficient (1 is less than 25801). Euler's totient φ(25801) = 25800 numbers up to 25801 share no factor with it.
- 4
The digits of 25801 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 77 steps to reach 1.
25801 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 25802 |
| Euler totient φ(n) | 25800 |
| Square | 665691601 |
| Cube | 17175508997401 |
| Square root | 160.626897 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 77 |
| Scientific notation | 2.5801 × |
25801 in other forms
| Form | Value |
|---|---|
| In words | twenty-five thousand eight hundred and one |
| Binary (base 2) | 110010011001001 |
| Octal (base 8) | 62311 |
| Hexadecimal (base 16) | 64C9 |
| Base 3 | 1022101121 |
| As time | 25801 seconds = 7 h 10 min 1 s |
Is 25801 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 1) | 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 1) | 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 7) | 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 | No (remainder 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 25801 a prime number?
Yes. 25801 is divisible only by 1 and itself.
What are the factors of 25801?
1, 25801.
What is 25801 in binary?
110010011001001 (hexadecimal 64C9, octal 62311).
What is the square root of 25801?
About 160.6269.
Is 25801 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 25801?
25801 is a twin prime (25799 and 25801 are both prime); the 2841st prime number; a happy number: repeatedly adding the squares of its digits reaches 1.