The number 29821
29821 is a composite number with 4 divisors. Its prime factorisation is 11 × 2711. Divisors (4): 1, 11, 2711, 29821.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 29821: a semiprime: 11 × 2711, the product of two primes.
- 2
29821 is composite. Its prime factorisation is
- 3
The divisors add up to 32544; without 29821 itself that is 2723, so 29821 is deficient (2723 is less than 29821). Euler's totient φ(29821) = 27100 numbers up to 29821 share no factor with it.
- 4
The digits of 29821 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 72 steps to reach 1.
LaTeX source of the formulas on this page
\[ 29821 = 11 \times 2711 \]
29821 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 32544 |
| Euler totient φ(n) | 27100 |
| Square | 889292041 |
| Cube | 26519577954661 |
| Square root | 172.687579 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 72 |
| Scientific notation | 2.9821 × |
29821 in other forms
| Form | Value |
|---|---|
| In words | twenty-nine thousand eight hundred and twenty-one |
| Binary (base 2) | 111010001111101 |
| Octal (base 8) | 72175 |
| Hexadecimal (base 16) | 747D |
| Base 3 | 1111220111 |
| As time | 29821 seconds = 8 h 17 min 1 s |
Is 29821 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 1) | 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 4) | 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 (29821 ÷ 11 = 2711) | 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 29821 a prime number?
No. 29821 = 11 × 2711, so it is divisible by 11.
What are the factors of 29821?
1, 11, 2711, 29821.
What is 29821 in binary?
111010001111101 (hexadecimal 747D, octal 72175).
What is the square root of 29821?
About 172.6876.
Is 29821 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 29821?
29821 is a semiprime: 11 × 2711, the product of two primes.