The number 21394
21394 is a composite number with 8 divisors. Its prime factorisation is 2 × 19 × 563. Divisors (8): 1, 2, 19, 38, 563, 1126, 10697, 21394.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21394: a Harshad number: divisible by its digit sum 19.
- 2
21394 is composite. Its prime factorisation is
- 3
The divisors add up to 33840; without 21394 itself that is 12446, so 21394 is deficient (12446 is less than 21394). Euler's totient φ(21394) = 10116 numbers up to 21394 share no factor with it.
- 4
The digits of 21394 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 193 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21394 = 2 \times 19 \times 563 \]
21394 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 33840 |
| Euler totient φ(n) | 10116 |
| Square | 457703236 |
| Cube | 9792103030984 |
| Square root | 146.266879 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 193 |
| Scientific notation | 2.1394 × |
21394 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand three hundred and ninety-four |
| Binary (base 2) | 101001110010010 |
| Octal (base 8) | 51622 |
| Hexadecimal (base 16) | 5392 |
| Base 3 | 1002100101 |
| As time | 21394 seconds = 5 h 56 min 34 s |
Is 21394 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21394 ÷ 2 = 10697) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 2) | 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 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21394 a prime number?
No. 21394 = 2 × 19 × 563, so it is divisible by 2.
What are the factors of 21394?
1, 2, 19, 38, 563, 1126, 10697, 21394.
What is 21394 in binary?
101001110010010 (hexadecimal 5392, octal 51622).
What is the square root of 21394?
About 146.2669.
Is 21394 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 21394?
21394 is a Harshad number: divisible by its digit sum 19.