The number 12155
12155 is a composite number with 16 divisors. Its prime factorisation is 5 × 11 × 13 × 17. Divisors (16): 1, 5, 11, 13, 17, 55, 65, 85, 143, 187, 221, 715, 935, 1105, 2431, 12155.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
12155 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
12155 is composite. Its prime factorisation is
- 3
The divisors add up to 18144; without 12155 itself that is 5989, so 12155 is deficient (5989 is less than 12155). Euler's totient φ(12155) = 7680 numbers up to 12155 share no factor with it.
- 4
The digits of 12155 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 187 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12155 = 5 \times 11 \times 13 \times 17 \]
12155 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 18144 |
| Euler totient φ(n) | 7680 |
| Square | 147744025 |
| Cube | 1795828623875 |
| Square root | 110.249717 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 187 |
| Scientific notation | 1.2155 × |
12155 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand one hundred and fifty-five |
| Binary (base 2) | 10111101111011 |
| Octal (base 8) | 27573 |
| Hexadecimal (base 16) | 2F7B |
| Base 3 | 121200012 |
| As time | 12155 seconds = 3 h 22 min 35 s |
Is 12155 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (12155 ÷ 5 = 2431) | 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 3) | 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 3) | 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 (12155 ÷ 11 = 1105) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 12155 a prime number?
No. 12155 = 5 × 11 × 13 × 17, so it is divisible by 5.
What are the factors of 12155?
1, 5, 11, 13, 17, 55, 65, 85, 143, 187, 221, 715, 935, 1105, 2431, 12155.
What is 12155 in binary?
10111101111011 (hexadecimal 2F7B, octal 27573).
What is the square root of 12155?
About 110.2497.
Is 12155 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 12155?
It is a composite number with 16 divisors.