The number 21241
21241 is a composite number with 4 divisors. Its prime factorisation is 11 × 1931. Divisors (4): 1, 11, 1931, 21241.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21241: a semiprime: 11 × 1931, the product of two primes.
- 2
21241 is composite. Its prime factorisation is
- 3
The divisors add up to 23184; without 21241 itself that is 1943, so 21241 is deficient (1943 is less than 21241). Euler's totient φ(21241) = 19300 numbers up to 21241 share no factor with it.
- 4
The digits of 21241 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21241 = 11 \times 1931 \]
21241 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 23184 |
| Euler totient φ(n) | 19300 |
| Square | 451180081 |
| Cube | 9583516100521 |
| Square root | 145.742924 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1241 × |
21241 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand two hundred and forty-one |
| Binary (base 2) | 101001011111001 |
| Octal (base 8) | 51371 |
| Hexadecimal (base 16) | 52F9 |
| Base 3 | 1002010201 |
| As time | 21241 seconds = 5 h 54 min 1 s |
Is 21241 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | 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 (21241 ÷ 11 = 1931) | 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 21241 a prime number?
No. 21241 = 11 × 1931, so it is divisible by 11.
What are the factors of 21241?
1, 11, 1931, 21241.
What is 21241 in binary?
101001011111001 (hexadecimal 52F9, octal 51371).
What is the square root of 21241?
About 145.7429.
Is 21241 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 21241?
21241 is a semiprime: 11 × 1931, the product of two primes.