The number 345
345 is a composite number with 8 divisors. Its prime factorisation is 3 × 5 × 23. Divisors (8): 1, 3, 5, 15, 23, 69, 115, 345.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
345 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
345 is composite. Its prime factorisation is
- 3
The divisors add up to 576; without 345 itself that is 231, so 345 is deficient (231 is less than 345). Euler's totient φ(345) = 176 numbers up to 345 share no factor with it.
- 4
The digits of 345 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 125 steps to reach 1.
LaTeX source of the formulas on this page
\[ 345 = 3 \times 5 \times 23 \]
345 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 576 |
| Euler totient φ(n) | 176 |
| Square | 119025 |
| Cube | 41063625 |
| Square root | 18.574176 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 125 |
| Scientific notation | 3.45 × |
345 in other forms
| Form | Value |
|---|---|
| In words | three hundred and forty-five |
| Roman numerals | CCCXLV |
| Binary (base 2) | 101011001 |
| Octal (base 8) | 531 |
| Hexadecimal (base 16) | 159 |
| Base 3 | 110210 |
| As time | 345 seconds = 5 min 45 s |
Is 345 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 | Yes (345 ÷ 3 = 115) | 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 (345 ÷ 5 = 69) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 3) | 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 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 345 a prime number?
No. 345 = 3 × 5 × 23, so it is divisible by 3.
What are the factors of 345?
1, 3, 5, 15, 23, 69, 115, 345.
What is 345 in binary?
101011001 (hexadecimal 159, octal 531).
What is the square root of 345?
About 18.5742.
What is 345 in Roman numerals?
CCCXLV.
Is 345 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 345?
It is a composite number with 8 divisors.