The number 7280
7280 is a composite number with 40 divisors. Its prime factorisation is × 5 × 7 × 13. Divisors (40): 1, 2, 4, 5, 7, 8, 10, 13, 14, 16, 20, 26, 28, 35, 40, 52 … 7280.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
7280 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
7280 is composite. Its prime factorisation is
- 3
The divisors add up to 20832; without 7280 itself that is 13552, so 7280 is abundant (13552 is more than 7280). Euler's totient φ(7280) = 2304 numbers up to 7280 share no factor with it.
- 4
The digits of 7280 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 44 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7280 = 2^{4} \times 5 \times 7 \times 13 \]7280 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 40 |
| Sum of divisors | 20832 |
| Euler totient φ(n) | 2304 |
| Square | 52998400 |
| Cube | 385828352000 |
| Square root | 85.322916 (= 4√455) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 44 |
| Scientific notation | 7.28 × |
7280 in other forms
| Form | Value |
|---|---|
| In words | seven thousand two hundred and eighty |
| Binary (base 2) | 1110001110000 |
| Octal (base 8) | 16160 |
| Hexadecimal (base 16) | 1C70 |
| Base 3 | 100222122 |
| As time | 7280 seconds = 2 h 1 min 20 s |
Is 7280 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (7280 ÷ 2 = 3640) | 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 (7280 ÷ 4 = 1820) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (7280 ÷ 5 = 1456) | 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 | Yes (7280 ÷ 7 = 1040) | 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 (7280 ÷ 8 = 910) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (7280 ÷ 10 = 728) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | 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 7280 a prime number?
No. 7280 = × 5 × 7 × 13, so it is divisible by 2.
What are the factors of 7280?
1, 2, 4, 5, 7, 8, 10, 13, 14, 16, 20, 26, 28, 35, 40, 52, 56, 65, 70, 80, 91, 104, 112, 130, 140, 182, 208, 260, 280, 364, 455, 520, 560, 728, 910, 1040, 1456, 1820, 3640, 7280.
What is 7280 in binary?
1110001110000 (hexadecimal 1C70, octal 16160).
What is the square root of 7280?
About 85.3229, exactly 4√455.
Is 7280 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 7280?
It is a composite number with 40 divisors.