The number 21041
21041 is a composite number with 4 divisors. Its prime factorisation is 53 × 397. Divisors (4): 1, 53, 397, 21041.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21041: a semiprime: 53 × 397, the product of two primes.
- 2
21041 is composite. Its prime factorisation is
- 3
The divisors add up to 21492; without 21041 itself that is 451, so 21041 is deficient (451 is less than 21041). Euler's totient φ(21041) = 20592 numbers up to 21041 share no factor with it.
- 4
The digits of 21041 add up to 8, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 105 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21041 = 53 \times 397 \]
21041 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 21492 |
| Euler totient φ(n) | 20592 |
| Square | 442723681 |
| Cube | 9315348971921 |
| Square root | 145.055162 |
| Digit sum / digital root | 8 / 8 |
| Collatz steps to 1 | 105 |
| Scientific notation | 2.1041 × |
21041 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and forty-one |
| Binary (base 2) | 101001000110001 |
| Octal (base 8) | 51061 |
| Hexadecimal (base 16) | 5231 |
| Base 3 | 1001212022 |
| As time | 21041 seconds = 5 h 50 min 41 s |
Is 21041 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 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 1) | 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 9) | 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 21041 a prime number?
No. 21041 = 53 × 397, so it is divisible by 53.
What are the factors of 21041?
1, 53, 397, 21041.
What is 21041 in binary?
101001000110001 (hexadecimal 5231, octal 51061).
What is the square root of 21041?
About 145.0552.
Is 21041 divisible by 3?
No. Its digits add up to 8, which is not a multiple of 3.
What is special about the number 21041?
21041 is a semiprime: 53 × 397, the product of two primes.