The number 2840
2840 is a composite number with 16 divisors. Its prime factorisation is × 5 × 71. Divisors (16): 1, 2, 4, 5, 8, 10, 20, 40, 71, 142, 284, 355, 568, 710, 1420, 2840.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
2840 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
2840 is composite. Its prime factorisation is
- 3
The divisors add up to 6480; without 2840 itself that is 3640, so 2840 is abundant (3640 is more than 2840). Euler's totient φ(2840) = 1120 numbers up to 2840 share no factor with it.
- 4
The digits of 2840 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 35 steps to reach 1.
LaTeX source of the formulas on this page
\[ 2840 = 2^{3} \times 5 \times 71 \]2840 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 6480 |
| Euler totient φ(n) | 1120 |
| Square | 8065600 |
| Cube | 22906304000 |
| Square root | 53.291650 (= 2√710) |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 35 |
| Scientific notation | 2.84 × |
2840 in other forms
| Form | Value |
|---|---|
| In words | two thousand eight hundred and forty |
| Roman numerals | MMDCCCXL |
| Binary (base 2) | 101100011000 |
| Octal (base 8) | 5430 |
| Hexadecimal (base 16) | B18 |
| Base 3 | 10220012 |
| As time | 2840 seconds = 47 min 20 s |
Is 2840 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (2840 ÷ 2 = 1420) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (2840 ÷ 4 = 710) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (2840 ÷ 5 = 568) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 | Yes (2840 ÷ 8 = 355) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (2840 ÷ 10 = 284) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2840 a prime number?
No. 2840 = × 5 × 71, so it is divisible by 2.
What are the factors of 2840?
1, 2, 4, 5, 8, 10, 20, 40, 71, 142, 284, 355, 568, 710, 1420, 2840.
What is 2840 in binary?
101100011000 (hexadecimal B18, octal 5430).
What is the square root of 2840?
About 53.2917, exactly 2√710.
What is 2840 in Roman numerals?
MMDCCCXL.
Is 2840 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 2840?
It is a composite number with 16 divisors.