The number 19989
19989 is a composite number with 6 divisors. Its prime factorisation is × 2221. Divisors (6): 1, 3, 9, 2221, 6663, 19989.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
19989 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
19989 is composite. Its prime factorisation is
- 3
The divisors add up to 28886; without 19989 itself that is 8897, so 19989 is deficient (8897 is less than 19989). Euler's totient φ(19989) = 13320 numbers up to 19989 share no factor with it.
- 4
The digits of 19989 add up to 36, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 180 steps to reach 1.
LaTeX source of the formulas on this page
\[ 19989 = 3^{2} \times 2221 \]19989 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 28886 |
| Euler totient φ(n) | 13320 |
| Square | 399560121 |
| Cube | 7986807258669 |
| Square root | 141.382460 (= 3√2221) |
| Digit sum / digital root | 36 / 9 |
| Collatz steps to 1 | 180 |
| Scientific notation | 1.9989 × |
19989 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand nine hundred and eighty-nine |
| Binary (base 2) | 100111000010101 |
| Octal (base 8) | 47025 |
| Hexadecimal (base 16) | 4E15 |
| Base 3 | 1000102100 |
| As time | 19989 seconds = 5 h 33 min 9 s |
Is 19989 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 | Yes (19989 ÷ 3 = 6663) | 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 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (19989 ÷ 9 = 2221) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 19989 a prime number?
No. 19989 = × 2221, so it is divisible by 3.
What are the factors of 19989?
1, 3, 9, 2221, 6663, 19989.
What is 19989 in binary?
100111000010101 (hexadecimal 4E15, octal 47025).
What is the square root of 19989?
About 141.3825, exactly 3√2221.
Is 19989 divisible by 3?
Yes. Its digits add up to 36, a multiple of 3.
What is special about the number 19989?
It is a composite number with 6 divisors.