The number 21850
21850 is a composite number with 24 divisors. Its prime factorisation is 2 × × 19 × 23. Divisors (24): 1, 2, 5, 10, 19, 23, 25, 38, 46, 50, 95, 115, 190, 230, 437, 475 … 21850.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21850: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
21850 is composite. Its prime factorisation is
- 3
The divisors add up to 44640; without 21850 itself that is 22790, so 21850 is abundant (22790 is more than 21850). Euler's totient φ(21850) = 7920 numbers up to 21850 share no factor with it.
- 4
The digits of 21850 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 118 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21850 = 2 \times 5^{2} \times 19 \times 23 \]21850 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 44640 |
| Euler totient φ(n) | 7920 |
| Square | 477422500 |
| Cube | 10431681625000 |
| Square root | 147.817455 (= 5√874) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 118 |
| Scientific notation | 2.185 × |
21850 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand eight hundred and fifty |
| Binary (base 2) | 101010101011010 |
| Octal (base 8) | 52532 |
| Hexadecimal (base 16) | 555A |
| Base 3 | 1002222021 |
| As time | 21850 seconds = 6 h 4 min 10 s |
Is 21850 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21850 ÷ 2 = 10925) | 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 (21850 ÷ 5 = 4370) | 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 3) | 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 2) | 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 (21850 ÷ 10 = 2185) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 21850 a prime number?
No. 21850 = 2 × × 19 × 23, so it is divisible by 2.
What are the factors of 21850?
1, 2, 5, 10, 19, 23, 25, 38, 46, 50, 95, 115, 190, 230, 437, 475, 575, 874, 950, 1150, 2185, 4370, 10925, 21850.
What is 21850 in binary?
101010101011010 (hexadecimal 555A, octal 52532).
What is the square root of 21850?
About 147.8175, exactly 5√874.
Is 21850 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 21850?
21850 is a happy number: repeatedly adding the squares of its digits reaches 1.