The number 72721
72721 is a composite number with 6 divisors. Its prime factorisation is Ć 601. Divisors (6): 1, 11, 121, 601, 6611, 72721.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
72721 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
72721 is composite. Its prime factorisation is
- 3
The divisors add up to 80066; without 72721 itself that is 7345, so 72721 is deficient (7345 is less than 72721). Euler's totient Ļ(72721) = 66000 numbers up to 72721 share no factor with it.
- 4
The digits of 72721 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 143 steps to reach 1.
LaTeX source of the formulas on this page
\[ 72721 = 11^{2} \times 601 \]72721 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 80066 |
| Euler totient Ļ(n) | 66000 |
| Square | 5288343841 |
| Cube | 384573652461361 |
| Square root | 269.668315 (= 11ā601) |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 143 |
| Scientific notation | 7.2721 Ć |
72721 in other forms
| Form | Value |
|---|---|
| In words | seventy-two thousand seven hundred and twenty-one |
| Binary (base 2) | 10001110000010001 |
| Octal (base 8) | 216021 |
| Hexadecimal (base 16) | 11C11 |
| Base 3 | 10200202101 |
| As time | 72721 seconds = 20 h 12 min 1 s |
Is 72721 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 | No (remainder 1) | 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 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | 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 (72721 Ć· 11 = 6611) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 72721 a prime number?
No. 72721 = Ć 601, so it is divisible by 11.
What are the factors of 72721?
1, 11, 121, 601, 6611, 72721.
What is 72721 in binary?
10001110000010001 (hexadecimal 11C11, octal 216021).
What is the square root of 72721?
About 269.6683, exactly 11ā601.
Is 72721 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 72721?
It is a composite number with 6 divisors.