The number 20625
20625 is a composite number with 20 divisors. Its prime factorisation is 3 × × 11. Divisors (20): 1, 3, 5, 11, 15, 25, 33, 55, 75, 125, 165, 275, 375, 625, 825, 1375 … 20625.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20625: a Harshad number: divisible by its digit sum 15.
- 2
20625 is composite. Its prime factorisation is
- 3
The divisors add up to 37488; without 20625 itself that is 16863, so 20625 is deficient (16863 is less than 20625). Euler's totient φ(20625) = 10000 numbers up to 20625 share no factor with it.
- 4
The digits of 20625 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 87 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20625 = 3 \times 5^{4} \times 11 \]20625 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 37488 |
| Euler totient φ(n) | 10000 |
| Square | 425390625 |
| Cube | 8773681640625 |
| Square root | 143.614066 (= 25√33) |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 87 |
| Scientific notation | 2.0625 × |
20625 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand six hundred and twenty-five |
| Binary (base 2) | 101000010010001 |
| Octal (base 8) | 50221 |
| Hexadecimal (base 16) | 5091 |
| Base 3 | 1001021220 |
| As time | 20625 seconds = 5 h 43 min 45 s |
Is 20625 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 | Yes (20625 ÷ 3 = 6875) | 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 (20625 ÷ 5 = 4125) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 6) | 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 | Yes (20625 ÷ 11 = 1875) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20625 a prime number?
No. 20625 = 3 × × 11, so it is divisible by 3.
What are the factors of 20625?
1, 3, 5, 11, 15, 25, 33, 55, 75, 125, 165, 275, 375, 625, 825, 1375, 1875, 4125, 6875, 20625.
What is 20625 in binary?
101000010010001 (hexadecimal 5091, octal 50221).
What is the square root of 20625?
About 143.6141, exactly 25√33.
Is 20625 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 20625?
20625 is a Harshad number: divisible by its digit sum 15.