The number 21672
21672 is a composite number with 48 divisors. Its prime factorisation is × × 7 × 43. Divisors (48): 1, 2, 3, 4, 6, 7, 8, 9, 12, 14, 18, 21, 24, 28, 36, 42 … 21672.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21672: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.
- 2
21672 is composite. Its prime factorisation is
- 3
The divisors add up to 68640; without 21672 itself that is 46968, so 21672 is abundant (46968 is more than 21672). Euler's totient φ(21672) = 6048 numbers up to 21672 share no factor with it.
- 4
The digits of 21672 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21672 = 2^{3} \times 3^{2} \times 7 \times 43 \]21672 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 68640 |
| Euler totient φ(n) | 6048 |
| Square | 469675584 |
| Cube | 10178809256448 |
| Square root | 147.214130 (= 6√602) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1672 × |
21672 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand six hundred and seventy-two |
| Binary (base 2) | 101010010101000 |
| Octal (base 8) | 52250 |
| Hexadecimal (base 16) | 54A8 |
| Base 3 | 1002201200 |
| As time | 21672 seconds = 6 h 1 min 12 s |
Is 21672 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21672 ÷ 2 = 10836) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21672 ÷ 3 = 7224) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21672 ÷ 4 = 5418) | 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 | Yes (21672 ÷ 6 = 3612) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21672 ÷ 7 = 3096) | 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 | Yes (21672 ÷ 8 = 2709) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (21672 ÷ 9 = 2408) | 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 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (21672 ÷ 12 = 1806) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21672 a prime number?
No. 21672 = × × 7 × 43, so it is divisible by 2.
What are the factors of 21672?
1, 2, 3, 4, 6, 7, 8, 9, 12, 14, 18, 21, 24, 28, 36, 42, 43, 56, 63, 72, 84, 86, 126, 129, 168, 172, 252, 258, 301, 344, 387, 504, 516, 602, 774, 903, 1032, 1204, 1548, 1806, 2408, 2709, 3096, 3612, 5418, 7224, 10836, 21672.
What is 21672 in binary?
101010010101000 (hexadecimal 54A8, octal 52250).
What is the square root of 21672?
About 147.2141, exactly 6√602.
Is 21672 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 21672?
21672 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.