The number 31213
31213 is a palindrome: it reads 31213 backwards too. Its prime factorisation is Ć 13. Divisors (10): 1, 7, 13, 49, 91, 343, 637, 2401, 4459, 31213.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31213: a palindrome: it reads 31213 backwards too.
- 2
31213 is composite. Its prime factorisation is
- 3
The divisors add up to 39214; without 31213 itself that is 8001, so 31213 is deficient (8001 is less than 31213). Euler's totient Ļ(31213) = 24696 numbers up to 31213 share no factor with it.
- 4
The digits of 31213 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 147 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31213 = 7^{4} \times 13 \]31213 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 10 |
| Sum of divisors | 39214 |
| Euler totient Ļ(n) | 24696 |
| Square | 974251369 |
| Cube | 30409307980597 |
| Square root | 176.672012 (= 49ā13) |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 147 |
| Scientific notation | 3.1213 Ć |
31213 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand two hundred and thirteen |
| Binary (base 2) | 111100111101101 |
| Octal (base 8) | 74755 |
| Hexadecimal (base 16) | 79ED |
| Base 3 | 1120211001 |
| As time | 31213 seconds = 8 h 40 min 13 s |
Is 31213 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 3) | 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 | Yes (31213 Ć· 7 = 4459) | 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 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | 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 31213 a prime number?
No. 31213 = Ć 13, so it is divisible by 7.
What are the factors of 31213?
1, 7, 13, 49, 91, 343, 637, 2401, 4459, 31213.
What is 31213 in binary?
111100111101101 (hexadecimal 79ED, octal 74755).
What is the square root of 31213?
About 176.6720, exactly 49ā13.
Is 31213 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 31213?
31213 is a palindrome: it reads 31213 backwards too.