The number 33821
33821 is a composite number with 4 divisors. Its prime factorisation is 31 × 1091. Divisors (4): 1, 31, 1091, 33821.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 33821: a semiprime: 31 × 1091, the product of two primes.
- 2
33821 is composite. Its prime factorisation is
- 3
The divisors add up to 34944; without 33821 itself that is 1123, so 33821 is deficient (1123 is less than 33821). Euler's totient φ(33821) = 32700 numbers up to 33821 share no factor with it.
- 4
The digits of 33821 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 204 steps to reach 1.
LaTeX source of the formulas on this page
\[ 33821 = 31 \times 1091 \]
33821 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 34944 |
| Euler totient φ(n) | 32700 |
| Square | 1143860041 |
| Cube | 38686490446661 |
| Square root | 183.904867 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 204 |
| Scientific notation | 3.3821 × |
33821 in other forms
| Form | Value |
|---|---|
| In words | thirty-three thousand eight hundred and twenty-one |
| Binary (base 2) | 1000010000011101 |
| Octal (base 8) | 102035 |
| Hexadecimal (base 16) | 841D |
| Base 3 | 1201101122 |
| As time | 33821 seconds = 9 h 23 min 41 s |
Is 33821 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 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 8) | 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 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 33821 a prime number?
No. 33821 = 31 × 1091, so it is divisible by 31.
What are the factors of 33821?
1, 31, 1091, 33821.
What is 33821 in binary?
1000010000011101 (hexadecimal 841D, octal 102035).
What is the square root of 33821?
About 183.9049.
Is 33821 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 33821?
33821 is a semiprime: 31 × 1091, the product of two primes.