The number 2640
2640 is a composite number with 40 divisors. Its prime factorisation is × 3 × 5 × 11. Divisors (40): 1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 15, 16, 20, 22, 24, 30 … 2640.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 2640: a Harshad number: divisible by its digit sum 12.
- 2
2640 is composite. Its prime factorisation is
- 3
The divisors add up to 8928; without 2640 itself that is 6288, so 2640 is abundant (6288 is more than 2640). Euler's totient φ(2640) = 640 numbers up to 2640 share no factor with it.
- 4
The digits of 2640 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 115 steps to reach 1.
LaTeX source of the formulas on this page
\[ 2640 = 2^{4} \times 3 \times 5 \times 11 \]2640 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 40 |
| Sum of divisors | 8928 |
| Euler totient φ(n) | 640 |
| Square | 6969600 |
| Cube | 18399744000 |
| Square root | 51.380930 (= 4√165) |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 115 |
| Scientific notation | 2.64 × |
2640 in other forms
| Form | Value |
|---|---|
| In words | two thousand six hundred and forty |
| Roman numerals | MMDCXL |
| Binary (base 2) | 101001010000 |
| Octal (base 8) | 5120 |
| Hexadecimal (base 16) | A50 |
| Base 3 | 10121210 |
| As time | 2640 seconds = 44 min 0 s |
Is 2640 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (2640 ÷ 2 = 1320) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (2640 ÷ 3 = 880) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (2640 ÷ 4 = 660) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (2640 ÷ 5 = 528) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (2640 ÷ 6 = 440) | 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 | Yes (2640 ÷ 8 = 330) | 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 (2640 ÷ 10 = 264) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (2640 ÷ 11 = 240) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (2640 ÷ 12 = 220) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 2640 a prime number?
No. 2640 = × 3 × 5 × 11, so it is divisible by 2.
What are the factors of 2640?
1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 15, 16, 20, 22, 24, 30, 33, 40, 44, 48, 55, 60, 66, 80, 88, 110, 120, 132, 165, 176, 220, 240, 264, 330, 440, 528, 660, 880, 1320, 2640.
What is 2640 in binary?
101001010000 (hexadecimal A50, octal 5120).
What is the square root of 2640?
About 51.3809, exactly 4√165.
What is 2640 in Roman numerals?
MMDCXL.
Is 2640 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 2640?
2640 is a Harshad number: divisible by its digit sum 12.