The number 97821
97821 is a composite number with 8 divisors. Its prime factorisation is × 3623. Divisors (8): 1, 3, 9, 27, 3623, 10869, 32607, 97821.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 97821: a Harshad number: divisible by its digit sum 27.
- 2
97821 is composite. Its prime factorisation is
- 3
The divisors add up to 144960; without 97821 itself that is 47139, so 97821 is deficient (47139 is less than 97821). Euler's totient φ(97821) = 65196 numbers up to 97821 share no factor with it.
- 4
The digits of 97821 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 159 steps to reach 1.
LaTeX source of the formulas on this page
\[ 97821 = 3^{3} \times 3623 \]97821 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 144960 |
| Euler totient φ(n) | 65196 |
| Square | 9568948041 |
| Cube | 936044066318661 |
| Square root | 312.763489 (= 3√10869) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 159 |
| Scientific notation | 9.7821 × |
97821 in other forms
| Form | Value |
|---|---|
| In words | ninety-seven thousand eight hundred and twenty-one |
| Binary (base 2) | 10111111000011101 |
| Octal (base 8) | 277035 |
| Hexadecimal (base 16) | 17E1D |
| Base 3 | 11222012000 |
| As time | 97821 seconds = 27 h 10 min 21 s |
Is 97821 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 (97821 ÷ 3 = 32607) | 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 3) | 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 | Yes (97821 ÷ 9 = 10869) | 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 9) | 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 97821 a prime number?
No. 97821 = × 3623, so it is divisible by 3.
What are the factors of 97821?
1, 3, 9, 27, 3623, 10869, 32607, 97821.
What is 97821 in binary?
10111111000011101 (hexadecimal 17E1D, octal 277035).
What is the square root of 97821?
About 312.7635, exactly 3√10869.
Is 97821 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 97821?
97821 is a Harshad number: divisible by its digit sum 27.