The number 21320
21320 is a composite number with 32 divisors. Its prime factorisation is × 5 × 13 × 41. Divisors (32): 1, 2, 4, 5, 8, 10, 13, 20, 26, 40, 41, 52, 65, 82, 104, 130 … 21320.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21320: a Harshad number: divisible by its digit sum 8.
- 2
21320 is composite. Its prime factorisation is
- 3
The divisors add up to 52920; without 21320 itself that is 31600, so 21320 is abundant (31600 is more than 21320). Euler's totient φ(21320) = 7680 numbers up to 21320 share no factor with it.
- 4
The digits of 21320 add up to 8, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21320 = 2^{3} \times 5 \times 13 \times 41 \]21320 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 52920 |
| Euler totient φ(n) | 7680 |
| Square | 454542400 |
| Cube | 9690843968000 |
| Square root | 146.013698 (= 2√5330) |
| Digit sum / digital root | 8 / 8 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.132 × |
21320 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand three hundred and twenty |
| Binary (base 2) | 101001101001000 |
| Octal (base 8) | 51510 |
| Hexadecimal (base 16) | 5348 |
| Base 3 | 1002020122 |
| As time | 21320 seconds = 5 h 55 min 20 s |
Is 21320 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21320 ÷ 2 = 10660) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21320 ÷ 4 = 5330) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (21320 ÷ 5 = 4264) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 | Yes (21320 ÷ 8 = 2665) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21320 ÷ 10 = 2132) | 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 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21320 a prime number?
No. 21320 = × 5 × 13 × 41, so it is divisible by 2.
What are the factors of 21320?
1, 2, 4, 5, 8, 10, 13, 20, 26, 40, 41, 52, 65, 82, 104, 130, 164, 205, 260, 328, 410, 520, 533, 820, 1066, 1640, 2132, 2665, 4264, 5330, 10660, 21320.
What is 21320 in binary?
101001101001000 (hexadecimal 5348, octal 51510).
What is the square root of 21320?
About 146.0137, exactly 2√5330.
Is 21320 divisible by 3?
No. Its digits add up to 8, which is not a multiple of 3.
What is special about the number 21320?
21320 is a Harshad number: divisible by its digit sum 8.