The number 19890
19890 is a composite number with 48 divisors. Its prime factorisation is 2 × × 5 × 13 × 17. Divisors (48): 1, 2, 3, 5, 6, 9, 10, 13, 15, 17, 18, 26, 30, 34, 39, 45 … 19890.
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How to work it out
- 1
19890 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
19890 is composite. Its prime factorisation is
- 3
The divisors add up to 58968; without 19890 itself that is 39078, so 19890 is abundant (39078 is more than 19890). Euler's totient φ(19890) = 4608 numbers up to 19890 share no factor with it.
- 4
The digits of 19890 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 74 steps to reach 1.
LaTeX source of the formulas on this page
\[ 19890 = 2 \times 3^{2} \times 5 \times 13 \times 17 \]19890 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 58968 |
| Euler totient φ(n) | 4608 |
| Square | 395612100 |
| Cube | 7868724669000 |
| Square root | 141.031911 (= 3√2210) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 74 |
| Scientific notation | 1.989 × |
19890 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand eight hundred and ninety |
| Binary (base 2) | 100110110110010 |
| Octal (base 8) | 46662 |
| Hexadecimal (base 16) | 4DB2 |
| Base 3 | 1000021200 |
| As time | 19890 seconds = 5 h 31 min 30 s |
Is 19890 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (19890 ÷ 2 = 9945) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (19890 ÷ 3 = 6630) | 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 (19890 ÷ 5 = 3978) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (19890 ÷ 6 = 3315) | 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 | Yes (19890 ÷ 9 = 2210) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (19890 ÷ 10 = 1989) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 19890 a prime number?
No. 19890 = 2 × × 5 × 13 × 17, so it is divisible by 2.
What are the factors of 19890?
1, 2, 3, 5, 6, 9, 10, 13, 15, 17, 18, 26, 30, 34, 39, 45, 51, 65, 78, 85, 90, 102, 117, 130, 153, 170, 195, 221, 234, 255, 306, 390, 442, 510, 585, 663, 765, 1105, 1170, 1326, 1530, 1989, 2210, 3315, 3978, 6630, 9945, 19890.
What is 19890 in binary?
100110110110010 (hexadecimal 4DB2, octal 46662).
What is the square root of 19890?
About 141.0319, exactly 3√2210.
Is 19890 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 19890?
It is a composite number with 48 divisors.