The number 21560
21560 is a composite number with 48 divisors. Its prime factorisation is × 5 × × 11. Divisors (48): 1, 2, 4, 5, 7, 8, 10, 11, 14, 20, 22, 28, 35, 40, 44, 49 … 21560.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21560: a Harshad number: divisible by its digit sum 14.
- 2
21560 is composite. Its prime factorisation is
- 3
The divisors add up to 61560; without 21560 itself that is 40000, so 21560 is abundant (40000 is more than 21560). Euler's totient φ(21560) = 6720 numbers up to 21560 share no factor with it.
- 4
The digits of 21560 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 30 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21560 = 2^{3} \times 5 \times 7^{2} \times 11 \]21560 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 61560 |
| Euler totient φ(n) | 6720 |
| Square | 464833600 |
| Cube | 10021812416000 |
| Square root | 146.833239 (= 14√110) |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 30 |
| Scientific notation | 2.156 × |
21560 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand five hundred and sixty |
| Binary (base 2) | 101010000111000 |
| Octal (base 8) | 52070 |
| Hexadecimal (base 16) | 5438 |
| Base 3 | 1002120112 |
| As time | 21560 seconds = 5 h 59 min 20 s |
Is 21560 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21560 ÷ 2 = 10780) | 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 (21560 ÷ 4 = 5390) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (21560 ÷ 5 = 4312) | 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 | Yes (21560 ÷ 7 = 3080) | 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 (21560 ÷ 8 = 2695) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21560 ÷ 10 = 2156) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (21560 ÷ 11 = 1960) | 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 21560 a prime number?
No. 21560 = × 5 × × 11, so it is divisible by 2.
What are the factors of 21560?
1, 2, 4, 5, 7, 8, 10, 11, 14, 20, 22, 28, 35, 40, 44, 49, 55, 56, 70, 77, 88, 98, 110, 140, 154, 196, 220, 245, 280, 308, 385, 392, 440, 490, 539, 616, 770, 980, 1078, 1540, 1960, 2156, 2695, 3080, 4312, 5390, 10780, 21560.
What is 21560 in binary?
101010000111000 (hexadecimal 5438, octal 52070).
What is the square root of 21560?
About 146.8332, exactly 14√110.
Is 21560 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 21560?
21560 is a Harshad number: divisible by its digit sum 14.