The number 365
365 is a binary palindrome (101101101). Its prime factorisation is 5 × 73. Divisors (4): 1, 5, 73, 365.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 365: a binary palindrome (101101101); a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 5 × 73, the product of two primes.
- 2
365 is composite. Its prime factorisation is
- 3
The divisors add up to 444; without 365 itself that is 79, so 365 is deficient (79 is less than 365). Euler's totient φ(365) = 288 numbers up to 365 share no factor with it.
- 4
The digits of 365 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 94 steps to reach 1.
LaTeX source of the formulas on this page
\[ 365 = 5 \times 73 \]
365 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 444 |
| Euler totient φ(n) | 288 |
| Square | 133225 |
| Cube | 48627125 |
| Square root | 19.104973 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 94 |
| Scientific notation | 3.65 × |
365 in other forms
| Form | Value |
|---|---|
| In words | three hundred and sixty-five |
| Roman numerals | CCCLXV |
| Binary (base 2) | 101101101 |
| Octal (base 8) | 555 |
| Hexadecimal (base 16) | 16D |
| Base 3 | 111112 |
| As time | 365 seconds = 6 min 5 s |
Is 365 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 (365 ÷ 5 = 73) | 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 1) | 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 5) | 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 | No (remainder 2) | 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 365 a prime number?
No. 365 = 5 × 73, so it is divisible by 5.
What are the factors of 365?
1, 5, 73, 365.
What is 365 in binary?
101101101 (hexadecimal 16D, octal 555).
What is the square root of 365?
About 19.1050.
What is 365 in Roman numerals?
CCCLXV.
Is 365 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 365?
365 is a binary palindrome (101101101); a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 5 × 73, the product of two primes.