The number 89721
89721 is a composite number with 8 divisors. Its prime factorisation is × 3323. Divisors (8): 1, 3, 9, 27, 3323, 9969, 29907, 89721.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 89721: a Harshad number: divisible by its digit sum 27.
- 2
89721 is composite. Its prime factorisation is
- 3
The divisors add up to 132960; without 89721 itself that is 43239, so 89721 is deficient (43239 is less than 89721). Euler's totient φ(89721) = 59796 numbers up to 89721 share no factor with it.
- 4
The digits of 89721 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 208 steps to reach 1.
LaTeX source of the formulas on this page
\[ 89721 = 3^{3} \times 3323 \]89721 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 132960 |
| Euler totient φ(n) | 59796 |
| Square | 8049857841 |
| Cube | 722241295352361 |
| Square root | 299.534639 (= 3√9969) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 208 |
| Scientific notation | 8.9721 × |
89721 in other forms
| Form | Value |
|---|---|
| In words | eighty-nine thousand seven hundred and twenty-one |
| Binary (base 2) | 10101111001111001 |
| Octal (base 8) | 257171 |
| Hexadecimal (base 16) | 15E79 |
| Base 3 | 11120002000 |
| As time | 89721 seconds = 24 h 55 min 21 s |
Is 89721 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 (89721 ÷ 3 = 29907) | 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (89721 ÷ 9 = 9969) | 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 | 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 89721 a prime number?
No. 89721 = × 3323, so it is divisible by 3.
What are the factors of 89721?
1, 3, 9, 27, 3323, 9969, 29907, 89721.
What is 89721 in binary?
10101111001111001 (hexadecimal 15E79, octal 257171).
What is the square root of 89721?
About 299.5346, exactly 3√9969.
Is 89721 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 89721?
89721 is a Harshad number: divisible by its digit sum 27.