The number 25513
25513 is a composite number with 4 divisors. Its prime factorisation is 31 × 823. Divisors (4): 1, 31, 823, 25513.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 25513: a semiprime: 31 × 823, the product of two primes.
- 2
25513 is composite. Its prime factorisation is
- 3
The divisors add up to 26368; without 25513 itself that is 855, so 25513 is deficient (855 is less than 25513). Euler's totient φ(25513) = 24660 numbers up to 25513 share no factor with it.
- 4
The digits of 25513 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 201 steps to reach 1.
LaTeX source of the formulas on this page
\[ 25513 = 31 \times 823 \]
25513 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 26368 |
| Euler totient φ(n) | 24660 |
| Square | 650913169 |
| Cube | 16606747680697 |
| Square root | 159.727894 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 201 |
| Scientific notation | 2.5513 × |
25513 in other forms
| Form | Value |
|---|---|
| In words | twenty-five thousand five hundred and thirteen |
| Binary (base 2) | 110001110101001 |
| Octal (base 8) | 61651 |
| Hexadecimal (base 16) | 63A9 |
| Base 3 | 1021222221 |
| As time | 25513 seconds = 7 h 5 min 13 s |
Is 25513 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 3) | 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 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 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 25513 a prime number?
No. 25513 = 31 × 823, so it is divisible by 31.
What are the factors of 25513?
1, 31, 823, 25513.
What is 25513 in binary?
110001110101001 (hexadecimal 63A9, octal 61651).
What is the square root of 25513?
About 159.7279.
Is 25513 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 25513?
25513 is a semiprime: 31 × 823, the product of two primes.