The number 9890
9890 is a composite number with 16 divisors. Its prime factorisation is 2 × 5 × 23 × 43. Divisors (16): 1, 2, 5, 10, 23, 43, 46, 86, 115, 215, 230, 430, 989, 1978, 4945, 9890.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 9890: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
9890 is composite. Its prime factorisation is
- 3
The divisors add up to 19008; without 9890 itself that is 9118, so 9890 is deficient (9118 is less than 9890). Euler's totient φ(9890) = 3696 numbers up to 9890 share no factor with it.
- 4
The digits of 9890 add up to 26, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 122 steps to reach 1.
LaTeX source of the formulas on this page
\[ 9890 = 2 \times 5 \times 23 \times 43 \]
9890 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 19008 |
| Euler totient φ(n) | 3696 |
| Square | 97812100 |
| Cube | 967361669000 |
| Square root | 99.448479 |
| Digit sum / digital root | 26 / 8 |
| Collatz steps to 1 | 122 |
| Scientific notation | 9.89 × |
9890 in other forms
| Form | Value |
|---|---|
| In words | nine thousand eight hundred and ninety |
| Binary (base 2) | 10011010100010 |
| Octal (base 8) | 23242 |
| Hexadecimal (base 16) | 26A2 |
| Base 3 | 111120022 |
| As time | 9890 seconds = 2 h 44 min 50 s |
Is 9890 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (9890 ÷ 2 = 4945) | 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 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (9890 ÷ 5 = 1978) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 2) | 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 | Yes (9890 ÷ 10 = 989) | 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 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 9890 a prime number?
No. 9890 = 2 × 5 × 23 × 43, so it is divisible by 2.
What are the factors of 9890?
1, 2, 5, 10, 23, 43, 46, 86, 115, 215, 230, 430, 989, 1978, 4945, 9890.
What is 9890 in binary?
10011010100010 (hexadecimal 26A2, octal 23242).
What is the square root of 9890?
About 99.4485.
Is 9890 divisible by 3?
No. Its digits add up to 26, which is not a multiple of 3.
What is special about the number 9890?
9890 is a happy number: repeatedly adding the squares of its digits reaches 1.