The number 21442
21442 is a composite number with 8 divisors. Its prime factorisation is 2 × 71 × 151. Divisors (8): 1, 2, 71, 142, 151, 302, 10721, 21442.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21442 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21442 is composite. Its prime factorisation is
- 3
The divisors add up to 32832; without 21442 itself that is 11390, so 21442 is deficient (11390 is less than 21442). Euler's totient φ(21442) = 10500 numbers up to 21442 share no factor with it.
- 4
The digits of 21442 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 100 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21442 = 2 \times 71 \times 151 \]
21442 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 32832 |
| Euler totient φ(n) | 10500 |
| Square | 459759364 |
| Cube | 9858160282888 |
| Square root | 146.430871 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1442 × |
21442 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and forty-two |
| Binary (base 2) | 101001111000010 |
| Octal (base 8) | 51702 |
| Hexadecimal (base 16) | 53C2 |
| Base 3 | 1002102011 |
| As time | 21442 seconds = 5 h 57 min 22 s |
Is 21442 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21442 ÷ 2 = 10721) | 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 2) | 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 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 2) | 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 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | 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 21442 a prime number?
No. 21442 = 2 × 71 × 151, so it is divisible by 2.
What are the factors of 21442?
1, 2, 71, 142, 151, 302, 10721, 21442.
What is 21442 in binary?
101001111000010 (hexadecimal 53C2, octal 51702).
What is the square root of 21442?
About 146.4309.
Is 21442 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 21442?
It is a composite number with 8 divisors.