The number 11989
11989 is a composite number with 4 divisors. Its prime factorisation is 19 × 631. Divisors (4): 1, 19, 631, 11989.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 11989: a semiprime: 19 × 631, the product of two primes.
- 2
11989 is composite. Its prime factorisation is
- 3
The divisors add up to 12640; without 11989 itself that is 651, so 11989 is deficient (651 is less than 11989). Euler's totient φ(11989) = 11340 numbers up to 11989 share no factor with it.
- 4
The digits of 11989 add up to 28, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 50 steps to reach 1.
LaTeX source of the formulas on this page
\[ 11989 = 19 \times 631 \]
11989 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 12640 |
| Euler totient φ(n) | 11340 |
| Square | 143736121 |
| Cube | 1723252354669 |
| Square root | 109.494292 |
| Digit sum / digital root | 28 / 1 |
| Collatz steps to 1 | 50 |
| Scientific notation | 1.1989 × |
11989 in other forms
| Form | Value |
|---|---|
| In words | eleven thousand nine hundred and eighty-nine |
| Binary (base 2) | 10111011010101 |
| Octal (base 8) | 27325 |
| Hexadecimal (base 16) | 2ED5 |
| Base 3 | 121110001 |
| As time | 11989 seconds = 3 h 19 min 49 s |
Is 11989 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 | No (remainder 4) | 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 5) | 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 | No (remainder 1) | 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 10) | 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 11989 a prime number?
No. 11989 = 19 × 631, so it is divisible by 19.
What are the factors of 11989?
1, 19, 631, 11989.
What is 11989 in binary?
10111011010101 (hexadecimal 2ED5, octal 27325).
What is the square root of 11989?
About 109.4943.
Is 11989 divisible by 3?
No. Its digits add up to 28, which is not a multiple of 3.
What is special about the number 11989?
11989 is a semiprime: 19 × 631, the product of two primes.