The number 12021
12021 is a palindrome: it reads 12021 backwards too. Its prime factorisation is 3 × 4007. Divisors (4): 1, 3, 4007, 12021.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 12021: a palindrome: it reads 12021 backwards too; a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 4007, the product of two primes.
- 2
12021 is composite. Its prime factorisation is
- 3
The divisors add up to 16032; without 12021 itself that is 4011, so 12021 is deficient (4011 is less than 12021). Euler's totient φ(12021) = 8012 numbers up to 12021 share no factor with it.
- 4
The digits of 12021 add up to 6, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 143 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12021 = 3 \times 4007 \]
12021 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 16032 |
| Euler totient φ(n) | 8012 |
| Square | 144504441 |
| Cube | 1737087885261 |
| Square root | 109.640321 |
| Digit sum / digital root | 6 / 6 |
| Collatz steps to 1 | 143 |
| Scientific notation | 1.2021 × |
12021 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand and twenty-one |
| Binary (base 2) | 10111011110101 |
| Octal (base 8) | 27365 |
| Hexadecimal (base 16) | 2EF5 |
| Base 3 | 121111020 |
| As time | 12021 seconds = 3 h 20 min 21 s |
Is 12021 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 (12021 ÷ 3 = 4007) | 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 1) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | 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 12021 a prime number?
No. 12021 = 3 × 4007, so it is divisible by 3.
What are the factors of 12021?
1, 3, 4007, 12021.
What is 12021 in binary?
10111011110101 (hexadecimal 2EF5, octal 27365).
What is the square root of 12021?
About 109.6403.
Is 12021 divisible by 3?
Yes. Its digits add up to 6, a multiple of 3.
What is special about the number 12021?
12021 is a palindrome: it reads 12021 backwards too; a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 4007, the product of two primes.