The number 1265
1265 is a composite number with 8 divisors. Its prime factorisation is 5 × 11 × 23. Divisors (8): 1, 5, 11, 23, 55, 115, 253, 1265.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
1265 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
1265 is composite. Its prime factorisation is
- 3
The divisors add up to 1728; without 1265 itself that is 463, so 1265 is deficient (463 is less than 1265). Euler's totient φ(1265) = 880 numbers up to 1265 share no factor with it.
- 4
The digits of 1265 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 39 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1265 = 5 \times 11 \times 23 \]
1265 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 1728 |
| Euler totient φ(n) | 880 |
| Square | 1600225 |
| Cube | 2024284625 |
| Square root | 35.566838 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 39 |
| Scientific notation | 1.265 × |
1265 in other forms
| Form | Value |
|---|---|
| In words | one thousand two hundred and sixty-five |
| Roman numerals | MCCLXV |
| Binary (base 2) | 10011110001 |
| Octal (base 8) | 2361 |
| Hexadecimal (base 16) | 4F1 |
| Base 3 | 1201212 |
| As time | 1265 seconds = 21 min 5 s |
Is 1265 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 | Yes (1265 ÷ 5 = 253) | 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 | 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 5) | 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 (1265 ÷ 11 = 115) | 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 1265 a prime number?
No. 1265 = 5 × 11 × 23, so it is divisible by 5.
What are the factors of 1265?
1, 5, 11, 23, 55, 115, 253, 1265.
What is 1265 in binary?
10011110001 (hexadecimal 4F1, octal 2361).
What is the square root of 1265?
About 35.5668.
What is 1265 in Roman numerals?
MCCLXV.
Is 1265 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 1265?
It is a composite number with 8 divisors.