The number 19998
19998 is a composite number with 24 divisors. Its prime factorisation is 2 × × 11 × 101. Divisors (24): 1, 2, 3, 6, 9, 11, 18, 22, 33, 66, 99, 101, 198, 202, 303, 606 … 19998.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
19998 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
19998 is composite. Its prime factorisation is
- 3
The divisors add up to 47736; without 19998 itself that is 27738, so 19998 is abundant (27738 is more than 19998). Euler's totient φ(19998) = 6000 numbers up to 19998 share no factor with it.
- 4
The digits of 19998 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 92 steps to reach 1.
LaTeX source of the formulas on this page
\[ 19998 = 2 \times 3^{2} \times 11 \times 101 \]19998 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 47736 |
| Euler totient φ(n) | 6000 |
| Square | 399920004 |
| Cube | 7997600239992 |
| Square root | 141.414285 (= 3√2222) |
| Digit sum / digital root | 36 / 9 |
| Collatz steps to 1 | 92 |
| Scientific notation | 1.9998 × |
19998 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand nine hundred and ninety-eight |
| Binary (base 2) | 100111000011110 |
| Octal (base 8) | 47036 |
| Hexadecimal (base 16) | 4E1E |
| Base 3 | 1000102200 |
| As time | 19998 seconds = 5 h 33 min 18 s |
Is 19998 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (19998 ÷ 2 = 9999) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (19998 ÷ 3 = 6666) | 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 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (19998 ÷ 6 = 3333) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (19998 ÷ 9 = 2222) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (19998 ÷ 11 = 1818) | 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 19998 a prime number?
No. 19998 = 2 × × 11 × 101, so it is divisible by 2.
What are the factors of 19998?
1, 2, 3, 6, 9, 11, 18, 22, 33, 66, 99, 101, 198, 202, 303, 606, 909, 1111, 1818, 2222, 3333, 6666, 9999, 19998.
What is 19998 in binary?
100111000011110 (hexadecimal 4E1E, octal 47036).
What is the square root of 19998?
About 141.4143, exactly 3√2222.
Is 19998 divisible by 3?
Yes. Its digits add up to 36, a multiple of 3.
What is special about the number 19998?
It is a composite number with 24 divisors.