The number 21667
21667 is a composite number with 4 divisors. Its prime factorisation is 47 × 461. Divisors (4): 1, 47, 461, 21667.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21667: a semiprime: 47 × 461, the product of two primes.
- 2
21667 is composite. Its prime factorisation is
- 3
The divisors add up to 22176; without 21667 itself that is 509, so 21667 is deficient (509 is less than 21667). Euler's totient φ(21667) = 21160 numbers up to 21667 share no factor with it.
- 4
The digits of 21667 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 69 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21667 = 47 \times 461 \]
21667 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 22176 |
| Euler totient φ(n) | 21160 |
| Square | 469458889 |
| Cube | 10171765747963 |
| Square root | 147.197147 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 69 |
| Scientific notation | 2.1667 × |
21667 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand six hundred and sixty-seven |
| Binary (base 2) | 101010010100011 |
| Octal (base 8) | 52243 |
| Hexadecimal (base 16) | 54A3 |
| Base 3 | 1002201111 |
| As time | 21667 seconds = 6 h 1 min 7 s |
Is 21667 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 3) | 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 1) | 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 3) | 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 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21667 a prime number?
No. 21667 = 47 × 461, so it is divisible by 47.
What are the factors of 21667?
1, 47, 461, 21667.
What is 21667 in binary?
101010010100011 (hexadecimal 54A3, octal 52243).
What is the square root of 21667?
About 147.1971.
Is 21667 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 21667?
21667 is a semiprime: 47 × 461, the product of two primes.