The number 71640
71640 is a composite number with 48 divisors. Its prime factorisation is × × 5 × 199. Divisors (48): 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36 … 71640.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 71640: a Harshad number: divisible by its digit sum 18.
- 2
71640 is composite. Its prime factorisation is
- 3
The divisors add up to 234000; without 71640 itself that is 162360, so 71640 is abundant (162360 is more than 71640). Euler's totient φ(71640) = 19008 numbers up to 71640 share no factor with it.
- 4
The digits of 71640 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
\[ 71640 = 2^{3} \times 3^{2} \times 5 \times 199 \]71640 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 234000 |
| Euler totient φ(n) | 19008 |
| Square | 5132289600 |
| Cube | 367677226944000 |
| Square root | 267.656496 (= 6√1990) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 99 |
| Scientific notation | 7.164 × |
71640 in other forms
| Form | Value |
|---|---|
| In words | seventy-one thousand six hundred and forty |
| Binary (base 2) | 10001011111011000 |
| Octal (base 8) | 213730 |
| Hexadecimal (base 16) | 117D8 |
| Base 3 | 10122021100 |
| As time | 71640 seconds = 19 h 54 min 0 s |
Is 71640 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (71640 ÷ 2 = 35820) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (71640 ÷ 3 = 23880) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (71640 ÷ 4 = 17910) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (71640 ÷ 5 = 14328) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (71640 ÷ 6 = 11940) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 (71640 ÷ 8 = 8955) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (71640 ÷ 9 = 7960) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (71640 ÷ 10 = 7164) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (71640 ÷ 12 = 5970) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 71640 a prime number?
No. 71640 = × × 5 × 199, so it is divisible by 2.
What are the factors of 71640?
1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, 180, 199, 360, 398, 597, 796, 995, 1194, 1592, 1791, 1990, 2388, 2985, 3582, 3980, 4776, 5970, 7164, 7960, 8955, 11940, 14328, 17910, 23880, 35820, 71640.
What is 71640 in binary?
10001011111011000 (hexadecimal 117D8, octal 213730).
What is the square root of 71640?
About 267.6565, exactly 6√1990.
Is 71640 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 71640?
71640 is a Harshad number: divisible by its digit sum 18.