The number 31243
31243 is a composite number with 4 divisors. Its prime factorisation is 157 × 199. Divisors (4): 1, 157, 199, 31243.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31243: a semiprime: 157 × 199, the product of two primes.
- 2
31243 is composite. Its prime factorisation is
- 3
The divisors add up to 31600; without 31243 itself that is 357, so 31243 is deficient (357 is less than 31243). Euler's totient φ(31243) = 30888 numbers up to 31243 share no factor with it.
- 4
The digits of 31243 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 147 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31243 = 157 \times 199 \]
31243 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 31600 |
| Euler totient φ(n) | 30888 |
| Square | 976125049 |
| Cube | 30497074905907 |
| Square root | 176.756895 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 147 |
| Scientific notation | 3.1243 × |
31243 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand two hundred and forty-three |
| Binary (base 2) | 111101000001011 |
| Octal (base 8) | 75013 |
| Hexadecimal (base 16) | 7A0B |
| Base 3 | 1120212011 |
| As time | 31243 seconds = 8 h 40 min 43 s |
Is 31243 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 3) | 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 | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31243 a prime number?
No. 31243 = 157 × 199, so it is divisible by 157.
What are the factors of 31243?
1, 157, 199, 31243.
What is 31243 in binary?
111101000001011 (hexadecimal 7A0B, octal 75013).
What is the square root of 31243?
About 176.7569.
Is 31243 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 31243?
31243 is a semiprime: 157 × 199, the product of two primes.