The number 12121
12121 is a palindrome: it reads 12121 backwards too. Its prime factorisation is 17 × 23 × 31. Divisors (8): 1, 17, 23, 31, 391, 527, 713, 12121.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 12121: a palindrome: it reads 12121 backwards too.
- 2
12121 is composite. Its prime factorisation is
- 3
The divisors add up to 13824; without 12121 itself that is 1703, so 12121 is deficient (1703 is less than 12121). Euler's totient φ(12121) = 10560 numbers up to 12121 share no factor with it.
- 4
The digits of 12121 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 143 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12121 = 17 \times 23 \times 31 \]
12121 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 13824 |
| Euler totient φ(n) | 10560 |
| Square | 146918641 |
| Cube | 1780800847561 |
| Square root | 110.095413 |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 143 |
| Scientific notation | 1.2121 × |
12121 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand one hundred and twenty-one |
| Binary (base 2) | 10111101011001 |
| Octal (base 8) | 27531 |
| Hexadecimal (base 16) | 2F59 |
| Base 3 | 121121221 |
| As time | 12121 seconds = 3 h 22 min 1 s |
Is 12121 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 | No (remainder 1) | 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 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 7) | 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 10) | 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 12121 a prime number?
No. 12121 = 17 × 23 × 31, so it is divisible by 17.
What are the factors of 12121?
1, 17, 23, 31, 391, 527, 713, 12121.
What is 12121 in binary?
10111101011001 (hexadecimal 2F59, octal 27531).
What is the square root of 12121?
About 110.0954.
Is 12121 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 12121?
12121 is a palindrome: it reads 12121 backwards too.