The number 1585
1585 is a composite number with 4 divisors. Its prime factorisation is 5 × 317. Divisors (4): 1, 5, 317, 1585.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1585: a semiprime: 5 × 317, the product of two primes.
- 2
1585 is composite. Its prime factorisation is
- 3
The divisors add up to 1908; without 1585 itself that is 323, so 1585 is deficient (323 is less than 1585). Euler's totient φ(1585) = 1264 numbers up to 1585 share no factor with it.
- 4
The digits of 1585 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 78 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1585 = 5 \times 317 \]
1585 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1908 |
| Euler totient φ(n) | 1264 |
| Square | 2512225 |
| Cube | 3981876625 |
| Square root | 39.812058 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 78 |
| Scientific notation | 1.585 × |
1585 in other forms
| Form | Value |
|---|---|
| In words | one thousand five hundred and eighty-five |
| Roman numerals | MDLXXXV |
| Binary (base 2) | 11000110001 |
| Octal (base 8) | 3061 |
| Hexadecimal (base 16) | 631 |
| Base 3 | 2011201 |
| As time | 1585 seconds = 26 min 25 s |
Is 1585 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 (1585 ÷ 5 = 317) | 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 3) | 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 1) | 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 1) | 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 1585 a prime number?
No. 1585 = 5 × 317, so it is divisible by 5.
What are the factors of 1585?
1, 5, 317, 1585.
What is 1585 in binary?
11000110001 (hexadecimal 631, octal 3061).
What is the square root of 1585?
About 39.8121.
What is 1585 in Roman numerals?
MDLXXXV.
Is 1585 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 1585?
1585 is a semiprime: 5 × 317, the product of two primes.