The number 1345
1345 is a composite number with 4 divisors. Its prime factorisation is 5 × 269. Divisors (4): 1, 5, 269, 1345.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1345: a semiprime: 5 × 269, the product of two primes.
- 2
1345 is composite. Its prime factorisation is
- 3
The divisors add up to 1620; without 1345 itself that is 275, so 1345 is deficient (275 is less than 1345). Euler's totient φ(1345) = 1072 numbers up to 1345 share no factor with it.
- 4
The digits of 1345 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 114 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1345 = 5 \times 269 \]
1345 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1620 |
| Euler totient φ(n) | 1072 |
| Square | 1809025 |
| Cube | 2433138625 |
| Square root | 36.674242 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 114 |
| Scientific notation | 1.345 × |
1345 in other forms
| Form | Value |
|---|---|
| In words | one thousand three hundred and forty-five |
| Roman numerals | MCCCXLV |
| Binary (base 2) | 10101000001 |
| Octal (base 8) | 2501 |
| Hexadecimal (base 16) | 541 |
| Base 3 | 1211211 |
| As time | 1345 seconds = 22 min 25 s |
Is 1345 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 (1345 ÷ 5 = 269) | 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 3) | 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 1345 a prime number?
No. 1345 = 5 × 269, so it is divisible by 5.
What are the factors of 1345?
1, 5, 269, 1345.
What is 1345 in binary?
10101000001 (hexadecimal 541, octal 2501).
What is the square root of 1345?
About 36.6742.
What is 1345 in Roman numerals?
MCCCXLV.
Is 1345 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 1345?
1345 is a semiprime: 5 × 269, the product of two primes.