The number 20490
20490 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 5 × 683. Divisors (16): 1, 2, 3, 5, 6, 10, 15, 30, 683, 1366, 2049, 3415, 4098, 6830, 10245, 20490.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20490: a Harshad number: divisible by its digit sum 15.
- 2
20490 is composite. Its prime factorisation is
- 3
The divisors add up to 49248; without 20490 itself that is 28758, so 20490 is abundant (28758 is more than 20490). Euler's totient φ(20490) = 5456 numbers up to 20490 share no factor with it.
- 4
The digits of 20490 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 149 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20490 = 2 \times 3 \times 5 \times 683 \]
20490 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 49248 |
| Euler totient φ(n) | 5456 |
| Square | 419840100 |
| Cube | 8602523649000 |
| Square root | 143.143285 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 149 |
| Scientific notation | 2.049 × |
20490 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand four hundred and ninety |
| Binary (base 2) | 101000000001010 |
| Octal (base 8) | 50012 |
| Hexadecimal (base 16) | 500A |
| Base 3 | 1001002220 |
| As time | 20490 seconds = 5 h 41 min 30 s |
Is 20490 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (20490 ÷ 2 = 10245) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (20490 ÷ 3 = 6830) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (20490 ÷ 5 = 4098) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (20490 ÷ 6 = 3415) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 2) | 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 | Yes (20490 ÷ 10 = 2049) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20490 a prime number?
No. 20490 = 2 × 3 × 5 × 683, so it is divisible by 2.
What are the factors of 20490?
1, 2, 3, 5, 6, 10, 15, 30, 683, 1366, 2049, 3415, 4098, 6830, 10245, 20490.
What is 20490 in binary?
101000000001010 (hexadecimal 500A, octal 50012).
What is the square root of 20490?
About 143.1433.
Is 20490 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 20490?
20490 is a Harshad number: divisible by its digit sum 15.