The number 20790
20790 is a composite number with 64 divisors. Its prime factorisation is 2 × × 5 × 7 × 11. Divisors (64): 1, 2, 3, 5, 6, 7, 9, 10, 11, 14, 15, 18, 21, 22, 27, 30 … 20790.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20790: a Harshad number: divisible by its digit sum 18.
- 2
20790 is composite. Its prime factorisation is
- 3
The divisors add up to 69120; without 20790 itself that is 48330, so 20790 is abundant (48330 is more than 20790). Euler's totient φ(20790) = 4320 numbers up to 20790 share no factor with it.
- 4
The digits of 20790 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 87 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20790 = 2 \times 3^{3} \times 5 \times 7 \times 11 \]20790 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 64 |
| Sum of divisors | 69120 |
| Euler totient φ(n) | 4320 |
| Square | 432224100 |
| Cube | 8985939039000 |
| Square root | 144.187378 (= 3√2310) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 87 |
| Scientific notation | 2.079 × |
20790 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand seven hundred and ninety |
| Binary (base 2) | 101000100110110 |
| Octal (base 8) | 50466 |
| Hexadecimal (base 16) | 5136 |
| Base 3 | 1001112000 |
| As time | 20790 seconds = 5 h 46 min 30 s |
Is 20790 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (20790 ÷ 2 = 10395) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (20790 ÷ 3 = 6930) | 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 (20790 ÷ 5 = 4158) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (20790 ÷ 6 = 3465) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (20790 ÷ 7 = 2970) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (20790 ÷ 9 = 2310) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (20790 ÷ 10 = 2079) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (20790 ÷ 11 = 1890) | 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 20790 a prime number?
No. 20790 = 2 × × 5 × 7 × 11, so it is divisible by 2.
What are the factors of 20790?
1, 2, 3, 5, 6, 7, 9, 10, 11, 14, 15, 18, 21, 22, 27, 30, 33, 35, 42, 45, 54, 55, 63, 66, 70, 77, 90, 99, 105, 110, 126, 135, 154, 165, 189, 198, 210, 231, 270, 297, 315, 330, 378, 385, 462, 495, 594, 630, 693, 770, 945, 990, 1155, 1386, 1485, 1890, 2079, 2310, 2970, 3465, 4158, 6930, 10395, 20790.
What is 20790 in binary?
101000100110110 (hexadecimal 5136, octal 50466).
What is the square root of 20790?
About 144.1874, exactly 3√2310.
Is 20790 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 20790?
20790 is a Harshad number: divisible by its digit sum 18.