The number 985
985 is a composite number with 4 divisors. Its prime factorisation is 5 × 197. Divisors (4): 1, 5, 197, 985.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 985: a semiprime: 5 × 197, the product of two primes.
- 2
985 is composite. Its prime factorisation is
- 3
The divisors add up to 1188; without 985 itself that is 203, so 985 is deficient (203 is less than 985). Euler's totient φ(985) = 784 numbers up to 985 share no factor with it.
- 4
The digits of 985 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 23 steps to reach 1.
LaTeX source of the formulas on this page
\[ 985 = 5 \times 197 \]
985 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1188 |
| Euler totient φ(n) | 784 |
| Square | 970225 |
| Cube | 955671625 |
| Square root | 31.384710 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 23 |
| Scientific notation | 9.85 × |
985 in other forms
| Form | Value |
|---|---|
| In words | nine hundred and eighty-five |
| Roman numerals | CMLXXXV |
| Binary (base 2) | 1111011001 |
| Octal (base 8) | 1731 |
| Hexadecimal (base 16) | 3D9 |
| Base 3 | 1100111 |
| As time | 985 seconds = 16 min 25 s |
Is 985 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 | Yes (985 ÷ 5 = 197) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | 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 985 a prime number?
No. 985 = 5 × 197, so it is divisible by 5.
What are the factors of 985?
1, 5, 197, 985.
What is 985 in binary?
1111011001 (hexadecimal 3D9, octal 1731).
What is the square root of 985?
About 31.3847.
What is 985 in Roman numerals?
CMLXXXV.
Is 985 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 985?
985 is a semiprime: 5 × 197, the product of two primes.