The number 20500
20500 is a composite number with 24 divisors. Its prime factorisation is × × 41. Divisors (24): 1, 2, 4, 5, 10, 20, 25, 41, 50, 82, 100, 125, 164, 205, 250, 410 … 20500.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
20500 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
20500 is composite. Its prime factorisation is
- 3
The divisors add up to 45864; without 20500 itself that is 25364, so 20500 is abundant (25364 is more than 20500). Euler's totient φ(20500) = 8000 numbers up to 20500 share no factor with it.
- 4
The digits of 20500 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20500 = 2^{2} \times 5^{3} \times 41 \]20500 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 45864 |
| Euler totient φ(n) | 8000 |
| Square | 420250000 |
| Cube | 8615125000000 |
| Square root | 143.178211 (= 10√205) |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.05 × |
20500 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand five hundred |
| Binary (base 2) | 101000000010100 |
| Octal (base 8) | 50024 |
| Hexadecimal (base 16) | 5014 |
| Base 3 | 1001010021 |
| As time | 20500 seconds = 5 h 41 min 40 s |
Is 20500 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (20500 ÷ 2 = 10250) | 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 | Yes (20500 ÷ 4 = 5125) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (20500 ÷ 5 = 4100) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 4) | 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 | Yes (20500 ÷ 10 = 2050) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20500 a prime number?
No. 20500 = × × 41, so it is divisible by 2.
What are the factors of 20500?
1, 2, 4, 5, 10, 20, 25, 41, 50, 82, 100, 125, 164, 205, 250, 410, 500, 820, 1025, 2050, 4100, 5125, 10250, 20500.
What is 20500 in binary?
101000000010100 (hexadecimal 5014, octal 50024).
What is the square root of 20500?
About 143.1782, exactly 10√205.
Is 20500 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 20500?
It is a composite number with 24 divisors.