The number 73821
73821 is a composite number with 8 divisors. Its prime factorisation is 3 × 11 × 2237. Divisors (8): 1, 3, 11, 33, 2237, 6711, 24607, 73821.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
73821 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
73821 is composite. Its prime factorisation is
- 3
The divisors add up to 107424; without 73821 itself that is 33603, so 73821 is deficient (33603 is less than 73821). Euler's totient φ(73821) = 44720 numbers up to 73821 share no factor with it.
- 4
The digits of 73821 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 112 steps to reach 1.
LaTeX source of the formulas on this page
\[ 73821 = 3 \times 11 \times 2237 \]
73821 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 107424 |
| Euler totient φ(n) | 44720 |
| Square | 5449540041 |
| Cube | 402290495366661 |
| Square root | 271.700202 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 112 |
| Scientific notation | 7.3821 × |
73821 in other forms
| Form | Value |
|---|---|
| In words | seventy-three thousand eight hundred and twenty-one |
| Binary (base 2) | 10010000001011101 |
| Octal (base 8) | 220135 |
| Hexadecimal (base 16) | 1205D |
| Base 3 | 10202021010 |
| As time | 73821 seconds = 20 h 30 min 21 s |
Is 73821 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 (73821 ÷ 3 = 24607) | 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 6) | 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 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (73821 ÷ 11 = 6711) | 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 73821 a prime number?
No. 73821 = 3 × 11 × 2237, so it is divisible by 3.
What are the factors of 73821?
1, 3, 11, 33, 2237, 6711, 24607, 73821.
What is 73821 in binary?
10010000001011101 (hexadecimal 1205D, octal 220135).
What is the square root of 73821?
About 271.7002.
Is 73821 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 73821?
It is a composite number with 8 divisors.