The number 2820
2820 is a composite number with 24 divisors. Its prime factorisation is × 3 × 5 × 47. Divisors (24): 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 47, 60, 94, 141, 188 … 2820.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2820: a Harshad number: divisible by its digit sum 12.
- 2
2820 is composite. Its prime factorisation is
- 3
The divisors add up to 8064; without 2820 itself that is 5244, so 2820 is abundant (5244 is more than 2820). Euler's totient φ(2820) = 736 numbers up to 2820 share no factor with it.
- 4
The digits of 2820 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 35 steps to reach 1.
LaTeX source of the formulas on this page
\[ 2820 = 2^{2} \times 3 \times 5 \times 47 \]2820 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 8064 |
| Euler totient φ(n) | 736 |
| Square | 7952400 |
| Cube | 22425768000 |
| Square root | 53.103672 (= 2√705) |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 35 |
| Scientific notation | 2.82 × |
2820 in other forms
| Form | Value |
|---|---|
| In words | two thousand eight hundred and twenty |
| Roman numerals | MMDCCCXX |
| Binary (base 2) | 101100000100 |
| Octal (base 8) | 5404 |
| Hexadecimal (base 16) | B04 |
| Base 3 | 10212110 |
| As time | 2820 seconds = 47 min 0 s |
Is 2820 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (2820 ÷ 2 = 1410) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (2820 ÷ 3 = 940) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (2820 ÷ 4 = 705) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (2820 ÷ 5 = 564) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (2820 ÷ 6 = 470) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 (2820 ÷ 10 = 282) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (2820 ÷ 12 = 235) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2820 a prime number?
No. 2820 = × 3 × 5 × 47, so it is divisible by 2.
What are the factors of 2820?
1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 47, 60, 94, 141, 188, 235, 282, 470, 564, 705, 940, 1410, 2820.
What is 2820 in binary?
101100000100 (hexadecimal B04, octal 5404).
What is the square root of 2820?
About 53.1037, exactly 2√705.
What is 2820 in Roman numerals?
MMDCCCXX.
Is 2820 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 2820?
2820 is a Harshad number: divisible by its digit sum 12.