The number 21250
21250 is a composite number with 20 divisors. Its prime factorisation is 2 × × 17. Divisors (20): 1, 2, 5, 10, 17, 25, 34, 50, 85, 125, 170, 250, 425, 625, 850, 1250 … 21250.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21250: a Harshad number: divisible by its digit sum 10.
- 2
21250 is composite. Its prime factorisation is
- 3
The divisors add up to 42174; without 21250 itself that is 20924, so 21250 is deficient (20924 is less than 21250). Euler's totient φ(21250) = 8000 numbers up to 21250 share no factor with it.
- 4
The digits of 21250 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21250 = 2 \times 5^{4} \times 17 \]21250 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 42174 |
| Euler totient φ(n) | 8000 |
| Square | 451562500 |
| Cube | 9595703125000 |
| Square root | 145.773797 (= 25√34) |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.125 × |
21250 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand two hundred and fifty |
| Binary (base 2) | 101001100000010 |
| Octal (base 8) | 51402 |
| Hexadecimal (base 16) | 5302 |
| Base 3 | 1002011001 |
| As time | 21250 seconds = 5 h 54 min 10 s |
Is 21250 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21250 ÷ 2 = 10625) | 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 (21250 ÷ 5 = 4250) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21250 ÷ 10 = 2125) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | 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 21250 a prime number?
No. 21250 = 2 × × 17, so it is divisible by 2.
What are the factors of 21250?
1, 2, 5, 10, 17, 25, 34, 50, 85, 125, 170, 250, 425, 625, 850, 1250, 2125, 4250, 10625, 21250.
What is 21250 in binary?
101001100000010 (hexadecimal 5302, octal 51402).
What is the square root of 21250?
About 145.7738, exactly 25√34.
Is 21250 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 21250?
21250 is a Harshad number: divisible by its digit sum 10.