The number 12729
12729 is a composite number with 4 divisors. Its prime factorisation is 3 × 4243. Divisors (4): 1, 3, 4243, 12729.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 12729: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 4243, the product of two primes.
- 2
12729 is composite. Its prime factorisation is
- 3
The divisors add up to 16976; without 12729 itself that is 4247, so 12729 is deficient (4247 is less than 12729). Euler's totient φ(12729) = 8484 numbers up to 12729 share no factor with it.
- 4
The digits of 12729 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 107 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12729 = 3 \times 4243 \]
12729 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 16976 |
| Euler totient φ(n) | 8484 |
| Square | 162027441 |
| Cube | 2062447296489 |
| Square root | 112.822870 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 107 |
| Scientific notation | 1.2729 × |
12729 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand seven hundred and twenty-nine |
| Binary (base 2) | 11000110111001 |
| Octal (base 8) | 30671 |
| Hexadecimal (base 16) | 31B9 |
| Base 3 | 122110110 |
| As time | 12729 seconds = 3 h 32 min 9 s |
Is 12729 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 (12729 ÷ 3 = 4243) | 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 | No (remainder 4) | 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 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 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 9) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 12729 a prime number?
No. 12729 = 3 × 4243, so it is divisible by 3.
What are the factors of 12729?
1, 3, 4243, 12729.
What is 12729 in binary?
11000110111001 (hexadecimal 31B9, octal 30671).
What is the square root of 12729?
About 112.8229.
Is 12729 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 12729?
12729 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 4243, the product of two primes.