The number 19825
19825 is a composite number with 12 divisors. Its prime factorisation is × 13 × 61. Divisors (12): 1, 5, 13, 25, 61, 65, 305, 325, 793, 1525, 3965, 19825.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 19825: a Harshad number: divisible by its digit sum 25.
- 2
19825 is composite. Its prime factorisation is
- 3
The divisors add up to 26908; without 19825 itself that is 7083, so 19825 is deficient (7083 is less than 19825). Euler's totient φ(19825) = 14400 numbers up to 19825 share no factor with it.
- 4
The digits of 19825 add up to 25, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 136 steps to reach 1.
LaTeX source of the formulas on this page
\[ 19825 = 5^{2} \times 13 \times 61 \]19825 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 26908 |
| Euler totient φ(n) | 14400 |
| Square | 393030625 |
| Cube | 7791832140625 |
| Square root | 140.801278 (= 5√793) |
| Digit sum / digital root | 25 / 7 |
| Collatz steps to 1 | 136 |
| Scientific notation | 1.9825 × |
19825 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand eight hundred and twenty-five |
| Binary (base 2) | 100110101110001 |
| Octal (base 8) | 46561 |
| Hexadecimal (base 16) | 4D71 |
| Base 3 | 1000012021 |
| As time | 19825 seconds = 5 h 30 min 25 s |
Is 19825 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (19825 ÷ 5 = 3965) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 1) | 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 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 19825 a prime number?
No. 19825 = × 13 × 61, so it is divisible by 5.
What are the factors of 19825?
1, 5, 13, 25, 61, 65, 305, 325, 793, 1525, 3965, 19825.
What is 19825 in binary?
100110101110001 (hexadecimal 4D71, octal 46561).
What is the square root of 19825?
About 140.8013, exactly 5√793.
Is 19825 divisible by 3?
No. Its digits add up to 25, which is not a multiple of 3.
What is special about the number 19825?
19825 is a Harshad number: divisible by its digit sum 25.