The number 72171
72171 is a composite number with 18 divisors. Its prime factorisation is × 11. Divisors (18): 1, 3, 9, 11, 27, 33, 81, 99, 243, 297, 729, 891, 2187, 2673, 6561, 8019 … 72171.
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How to work it out
- 1
72171 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
72171 is composite. Its prime factorisation is
- 3
The divisors add up to 118092; without 72171 itself that is 45921, so 72171 is deficient (45921 is less than 72171). Euler's totient φ(72171) = 43740 numbers up to 72171 share no factor with it.
- 4
The digits of 72171 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
\[ 72171 = 3^{8} \times 11 \]72171 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 18 |
| Sum of divisors | 118092 |
| Euler totient φ(n) | 43740 |
| Square | 5208653241 |
| Cube | 375913713056211 |
| Square root | 268.646608 (= 81√11) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 99 |
| Scientific notation | 7.2171 × |
72171 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand one hundred and seventy-one |
| Binary (base 2) | 10001100111101011 |
| Octal (base 8) | 214753 |
| Hexadecimal (base 16) | 119EB |
| Base 3 | 10200000000 |
| As time | 72171 seconds = 20 h 2 min 51 s |
Is 72171 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (72171 ÷ 3 = 24057) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | 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 | No (remainder 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (72171 ÷ 9 = 8019) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (72171 ÷ 11 = 6561) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72171 a prime number?
No. 72171 = × 11, so it is divisible by 3.
What are the factors of 72171?
1, 3, 9, 11, 27, 33, 81, 99, 243, 297, 729, 891, 2187, 2673, 6561, 8019, 24057, 72171.
What is 72171 in binary?
10001100111101011 (hexadecimal 119EB, octal 214753).
What is the square root of 72171?
About 268.6466, exactly 81√11.
Is 72171 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 72171?
It is a composite number with 18 divisors.