The number 21941
21941 is a composite number with 4 divisors. Its prime factorisation is 37 × 593. Divisors (4): 1, 37, 593, 21941.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21941: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 37 × 593, the product of two primes.
- 2
21941 is composite. Its prime factorisation is
- 3
The divisors add up to 22572; without 21941 itself that is 631, so 21941 is deficient (631 is less than 21941). Euler's totient φ(21941) = 21312 numbers up to 21941 share no factor with it.
- 4
The digits of 21941 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 118 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21941 = 37 \times 593 \]
21941 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 22572 |
| Euler totient φ(n) | 21312 |
| Square | 481407481 |
| Cube | 10562561540621 |
| Square root | 148.124947 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 118 |
| Scientific notation | 2.1941 × |
21941 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand nine hundred and forty-one |
| Binary (base 2) | 101010110110101 |
| Octal (base 8) | 52665 |
| Hexadecimal (base 16) | 55B5 |
| Base 3 | 1010002122 |
| As time | 21941 seconds = 6 h 5 min 41 s |
Is 21941 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 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 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 21941 a prime number?
No. 21941 = 37 × 593, so it is divisible by 37.
What are the factors of 21941?
1, 37, 593, 21941.
What is 21941 in binary?
101010110110101 (hexadecimal 55B5, octal 52665).
What is the square root of 21941?
About 148.1249.
Is 21941 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21941?
21941 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 37 × 593, the product of two primes.