The number 1145
1145 is a composite number with 4 divisors. Its prime factorisation is 5 × 229. Divisors (4): 1, 5, 229, 1145.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 1145: a semiprime: 5 × 229, the product of two primes.
- 2
1145 is composite. Its prime factorisation is
- 3
The divisors add up to 1380; without 1145 itself that is 235, so 1145 is deficient (235 is less than 1145). Euler's totient φ(1145) = 912 numbers up to 1145 share no factor with it.
- 4
The digits of 1145 add up to 11, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 150 steps to reach 1.
LaTeX source of the formulas on this page
\[ 1145 = 5 \times 229 \]
1145 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 1380 |
| Euler totient φ(n) | 912 |
| Square | 1311025 |
| Cube | 1501123625 |
| Square root | 33.837849 |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 150 |
| Scientific notation | 1.145 × |
1145 in other forms
| Form | Value |
|---|---|
| In words | one thousand one hundred and forty-five |
| Roman numerals | MCXLV |
| Binary (base 2) | 10001111001 |
| Octal (base 8) | 2171 |
| Hexadecimal (base 16) | 479 |
| Base 3 | 1120102 |
| As time | 1145 seconds = 19 min 5 s |
Is 1145 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 (1145 ÷ 5 = 229) | 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 4) | 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 2) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 1145 a prime number?
No. 1145 = 5 × 229, so it is divisible by 5.
What are the factors of 1145?
1, 5, 229, 1145.
What is 1145 in binary?
10001111001 (hexadecimal 479, octal 2171).
What is the square root of 1145?
About 33.8378.
What is 1145 in Roman numerals?
MCXLV.
Is 1145 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 1145?
1145 is a semiprime: 5 × 229, the product of two primes.