The number 19889
19889 is a twin prime (19889 and 19891 are both prime) and the 2249th prime number. Its only divisors are 1 and 19889.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 19889: a twin prime (19889 and 19891 are both prime); the 2249th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
19889 is prime, so its only factors are 1 and 19889. It is the 2249th prime; the next prime is 19891 and the one before is 19867.
- 3
The divisors add up to 19890; without 19889 itself that is 1, so 19889 is deficient (1 is less than 19889). Euler's totient φ(19889) = 19888 numbers up to 19889 share no factor with it.
- 4
The digits of 19889 add up to 35, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 74 steps to reach 1.
19889 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 19890 |
| Euler totient φ(n) | 19888 |
| Square | 395572321 |
| Cube | 7867537892369 |
| Square root | 141.028366 |
| Digit sum / digital root | 35 / 8 |
| Collatz steps to 1 | 74 |
| Scientific notation | 1.9889 × |
19889 in other forms
| Form | Value |
|---|---|
| In words | nineteen thousand eight hundred and eighty-nine |
| Binary (base 2) | 100110110110001 |
| Octal (base 8) | 46661 |
| Hexadecimal (base 16) | 4DB1 |
| Base 3 | 1000021122 |
| As time | 19889 seconds = 5 h 31 min 29 s |
Is 19889 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 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 8) | 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 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 19889 a prime number?
Yes. 19889 is divisible only by 1 and itself.
What are the factors of 19889?
1, 19889.
What is 19889 in binary?
100110110110001 (hexadecimal 4DB1, octal 46661).
What is the square root of 19889?
About 141.0284.
Is 19889 divisible by 3?
No. Its digits add up to 35, which is not a multiple of 3.
What is special about the number 19889?
19889 is a twin prime (19889 and 19891 are both prime); the 2249th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.