The number 385
385 is a composite number with 8 divisors. Its prime factorisation is 5 × 7 × 11. Divisors (8): 1, 5, 7, 11, 35, 55, 77, 385.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
385 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
385 is composite. Its prime factorisation is
- 3
The divisors add up to 576; without 385 itself that is 191, so 385 is deficient (191 is less than 385). Euler's totient φ(385) = 240 numbers up to 385 share no factor with it.
- 4
The digits of 385 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 32 steps to reach 1.
LaTeX source of the formulas on this page
\[ 385 = 5 \times 7 \times 11 \]
385 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 576 |
| Euler totient φ(n) | 240 |
| Square | 148225 |
| Cube | 57066625 |
| Square root | 19.621417 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 32 |
| Scientific notation | 3.85 × |
385 in other forms
| Form | Value |
|---|---|
| In words | three hundred and eighty-five |
| Roman numerals | CCCLXXXV |
| Binary (base 2) | 110000001 |
| Octal (base 8) | 601 |
| Hexadecimal (base 16) | 181 |
| Base 3 | 112021 |
| As time | 385 seconds = 6 min 25 s |
Is 385 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 (385 ÷ 5 = 77) | 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 | Yes (385 ÷ 7 = 55) | 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 7) | 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 | Yes (385 ÷ 11 = 35) | 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 385 a prime number?
No. 385 = 5 × 7 × 11, so it is divisible by 5.
What are the factors of 385?
1, 5, 7, 11, 35, 55, 77, 385.
What is 385 in binary?
110000001 (hexadecimal 181, octal 601).
What is the square root of 385?
About 19.6214.
What is 385 in Roman numerals?
CCCLXXXV.
Is 385 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 385?
It is a composite number with 8 divisors.