The number 72165
72165 is a composite number with 16 divisors. Its prime factorisation is 3 × 5 × 17 × 283. Divisors (16): 1, 3, 5, 15, 17, 51, 85, 255, 283, 849, 1415, 4245, 4811, 14433, 24055, 72165.
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How to work it out
- 1
72165 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
72165 is composite. Its prime factorisation is
- 3
The divisors add up to 122688; without 72165 itself that is 50523, so 72165 is deficient (50523 is less than 72165). Euler's totient φ(72165) = 36096 numbers up to 72165 share no factor with it.
- 4
The digits of 72165 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 143 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72165 = 3 \times 5 \times 17 \times 283 \]
72165 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 122688 |
| Euler totient φ(n) | 36096 |
| Square | 5207787225 |
| Cube | 375819965092125 |
| Square root | 268.635441 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 143 |
| Scientific notation | 7.2165 × |
72165 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand one hundred and sixty-five |
| Binary (base 2) | 10001100111100101 |
| Octal (base 8) | 214745 |
| Hexadecimal (base 16) | 119E5 |
| Base 3 | 10122222210 |
| As time | 72165 seconds = 20 h 2 min 45 s |
Is 72165 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 (72165 ÷ 3 = 24055) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (72165 ÷ 5 = 14433) | 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 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 | No (remainder 5) | 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 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72165 a prime number?
No. 72165 = 3 × 5 × 17 × 283, so it is divisible by 3.
What are the factors of 72165?
1, 3, 5, 15, 17, 51, 85, 255, 283, 849, 1415, 4245, 4811, 14433, 24055, 72165.
What is 72165 in binary?
10001100111100101 (hexadecimal 119E5, octal 214745).
What is the square root of 72165?
About 268.6354.
Is 72165 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 72165?
It is a composite number with 16 divisors.