The number 9989
9989 is a composite number with 4 divisors. Its prime factorisation is 7 × 1427. Divisors (4): 1, 7, 1427, 9989.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 9989: a semiprime: 7 × 1427, the product of two primes.
- 2
9989 is composite. Its prime factorisation is
- 3
The divisors add up to 11424; without 9989 itself that is 1435, so 9989 is deficient (1435 is less than 9989). Euler's totient φ(9989) = 8556 numbers up to 9989 share no factor with it.
- 4
The digits of 9989 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 91 steps to reach 1.
LaTeX source of the formulas on this page
\[ 9989 = 7 \times 1427 \]
9989 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 11424 |
| Euler totient φ(n) | 8556 |
| Square | 99780121 |
| Cube | 996703628669 |
| Square root | 99.944985 |
| Digit sum / digital root | 35 / 8 |
| Collatz steps to 1 | 91 |
| Scientific notation | 9.989 × |
9989 in other forms
| Form | Value |
|---|---|
| In words | nine thousand nine hundred and eighty-nine |
| Binary (base 2) | 10011100000101 |
| Octal (base 8) | 23405 |
| Hexadecimal (base 16) | 2705 |
| Base 3 | 111200222 |
| As time | 9989 seconds = 2 h 46 min 29 s |
Is 9989 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 | Yes (9989 ÷ 7 = 1427) | 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 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 9989 a prime number?
No. 9989 = 7 × 1427, so it is divisible by 7.
What are the factors of 9989?
1, 7, 1427, 9989.
What is 9989 in binary?
10011100000101 (hexadecimal 2705, octal 23405).
What is the square root of 9989?
About 99.9450.
Is 9989 divisible by 3?
No. Its digits add up to 35, which is not a multiple of 3.
What is special about the number 9989?
9989 is a semiprime: 7 × 1427, the product of two primes.