The number 71280
71280 is a composite number with 100 divisors. Its prime factorisation is × × 5 × 11. Divisors (100): 1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 15, 16, 18, 20, 22 … 71280.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 71280: a Harshad number: divisible by its digit sum 18.
- 2
71280 is composite. Its prime factorisation is
- 3
The divisors add up to 270072; without 71280 itself that is 198792, so 71280 is abundant (198792 is more than 71280). Euler's totient φ(71280) = 17280 numbers up to 71280 share no factor with it.
- 4
The digits of 71280 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 99 steps to reach 1.
LaTeX source of the formulas on this page
\[ 71280 = 2^{4} \times 3^{4} \times 5 \times 11 \]71280 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 100 |
| Sum of divisors | 270072 |
| Euler totient φ(n) | 17280 |
| Square | 5080838400 |
| Cube | 362162161152000 |
| Square root | 266.983146 (= 36√55) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 99 |
| Scientific notation | 7.128 × |
71280 in other forms
| Form | Value |
|---|---|
| In words | seventy-one thousand two hundred and eighty |
| Binary (base 2) | 10001011001110000 |
| Octal (base 8) | 213160 |
| Hexadecimal (base 16) | 11670 |
| Base 3 | 10121210000 |
| As time | 71280 seconds = 19 h 48 min 0 s |
Is 71280 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (71280 ÷ 2 = 35640) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (71280 ÷ 3 = 23760) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (71280 ÷ 4 = 17820) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (71280 ÷ 5 = 14256) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (71280 ÷ 6 = 11880) | 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 | Yes (71280 ÷ 8 = 8910) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (71280 ÷ 9 = 7920) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (71280 ÷ 10 = 7128) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (71280 ÷ 11 = 6480) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (71280 ÷ 12 = 5940) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 71280 a prime number?
No. 71280 = × × 5 × 11, so it is divisible by 2.
What are the factors of 71280?
1, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 15, 16, 18, 20, 22, 24, 27, 30, 33, 36, 40, 44, 45, 48, 54, 55, 60, 66, 72, 80, 81, 88, 90, 99, 108, 110, 120, 132, 135, 144, 162, 165, 176, 180, 198, 216, 220, 240, 264, 270, 297, 324, 330, 360, 396, 405, 432, 440, 495, 528, 540, 594, 648, 660, 720, 792, 810, 880, 891, 990, 1080, 1188, 1296, 1320, 1485, 1584, 1620, 1782, 1980, 2160, 2376, 2640, 2970, 3240, 3564, 3960, 4455, 4752, 5940, 6480, 7128, 7920, 8910, 11880, 14256, 17820, 23760, 35640, 71280.
What is 71280 in binary?
10001011001110000 (hexadecimal 11670, octal 213160).
What is the square root of 71280?
About 266.9831, exactly 36√55.
Is 71280 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 71280?
71280 is a Harshad number: divisible by its digit sum 18.