The number 20725
20725 is a composite number with 6 divisors. Its prime factorisation is Ć 829. Divisors (6): 1, 5, 25, 829, 4145, 20725.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20725: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
20725 is composite. Its prime factorisation is
- 3
The divisors add up to 25730; without 20725 itself that is 5005, so 20725 is deficient (5005 is less than 20725). Euler's totient Ļ(20725) = 16560 numbers up to 20725 share no factor with it.
- 4
The digits of 20725 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 43 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20725 = 5^{2} \times 829 \]20725 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 25730 |
| Euler totient Ļ(n) | 16560 |
| Square | 429525625 |
| Cube | 8901918578125 |
| Square root | 143.961800 (= 5ā829) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 43 |
| Scientific notation | 2.0725 Ć |
20725 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand seven hundred and twenty-five |
| Binary (base 2) | 101000011110101 |
| Octal (base 8) | 50365 |
| Hexadecimal (base 16) | 50F5 |
| Base 3 | 1001102121 |
| As time | 20725 seconds = 5 h 45 min 25 s |
Is 20725 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 | Yes (20725 Ć· 5 = 4145) | 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 5) | 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 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | 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 20725 a prime number?
No. 20725 = Ć 829, so it is divisible by 5.
What are the factors of 20725?
1, 5, 25, 829, 4145, 20725.
What is 20725 in binary?
101000011110101 (hexadecimal 50F5, octal 50365).
What is the square root of 20725?
About 143.9618, exactly 5ā829.
Is 20725 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 20725?
20725 is a happy number: repeatedly adding the squares of its digits reaches 1.