The number 21670
21670 is a composite number with 16 divisors. Its prime factorisation is 2 × 5 × 11 × 197. Divisors (16): 1, 2, 5, 10, 11, 22, 55, 110, 197, 394, 985, 1970, 2167, 4334, 10835, 21670.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21670 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21670 is composite. Its prime factorisation is
- 3
The divisors add up to 42768; without 21670 itself that is 21098, so 21670 is deficient (21098 is less than 21670). Euler's totient φ(21670) = 7840 numbers up to 21670 share no factor with it.
- 4
The digits of 21670 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 69 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21670 = 2 \times 5 \times 11 \times 197 \]
21670 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 42768 |
| Euler totient φ(n) | 7840 |
| Square | 469588900 |
| Cube | 10175991463000 |
| Square root | 147.207337 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 69 |
| Scientific notation | 2.167 × |
21670 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand six hundred and seventy |
| Binary (base 2) | 101010010100110 |
| Octal (base 8) | 52246 |
| Hexadecimal (base 16) | 54A6 |
| Base 3 | 1002201121 |
| As time | 21670 seconds = 6 h 1 min 10 s |
Is 21670 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21670 ÷ 2 = 10835) | 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 | Yes (21670 ÷ 5 = 4334) | 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 5) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21670 ÷ 10 = 2167) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (21670 ÷ 11 = 1970) | 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 21670 a prime number?
No. 21670 = 2 × 5 × 11 × 197, so it is divisible by 2.
What are the factors of 21670?
1, 2, 5, 10, 11, 22, 55, 110, 197, 394, 985, 1970, 2167, 4334, 10835, 21670.
What is 21670 in binary?
101010010100110 (hexadecimal 54A6, octal 52246).
What is the square root of 21670?
About 147.2073.
Is 21670 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 21670?
It is a composite number with 16 divisors.