The number 20820
20820 is a composite number with 24 divisors. Its prime factorisation is × 3 × 5 × 347. Divisors (24): 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60, 347, 694, 1041, 1388 … 20820.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20820: a Harshad number: divisible by its digit sum 12.
- 2
20820 is composite. Its prime factorisation is
- 3
The divisors add up to 58464; without 20820 itself that is 37644, so 20820 is abundant (37644 is more than 20820). Euler's totient φ(20820) = 5536 numbers up to 20820 share no factor with it.
- 4
The digits of 20820 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 30 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20820 = 2^{2} \times 3 \times 5 \times 347 \]20820 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 58464 |
| Euler totient φ(n) | 5536 |
| Square | 433472400 |
| Cube | 9024895368000 |
| Square root | 144.291372 (= 2√5205) |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 30 |
| Scientific notation | 2.082 × |
20820 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand eight hundred and twenty |
| Binary (base 2) | 101000101010100 |
| Octal (base 8) | 50524 |
| Hexadecimal (base 16) | 5154 |
| Base 3 | 1001120010 |
| As time | 20820 seconds = 5 h 47 min 0 s |
Is 20820 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (20820 ÷ 2 = 10410) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (20820 ÷ 3 = 6940) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (20820 ÷ 4 = 5205) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (20820 ÷ 5 = 4164) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (20820 ÷ 6 = 3470) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (20820 ÷ 10 = 2082) | 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 | Yes (20820 ÷ 12 = 1735) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20820 a prime number?
No. 20820 = × 3 × 5 × 347, so it is divisible by 2.
What are the factors of 20820?
1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60, 347, 694, 1041, 1388, 1735, 2082, 3470, 4164, 5205, 6940, 10410, 20820.
What is 20820 in binary?
101000101010100 (hexadecimal 5154, octal 50524).
What is the square root of 20820?
About 144.2914, exactly 2√5205.
Is 20820 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 20820?
20820 is a Harshad number: divisible by its digit sum 12.