The number 31643
31643 is the 3403rd prime number. Its only divisors are 1 and 31643.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31643: the 3403rd prime number.
- 2
31643 is prime, so its only factors are 1 and 31643. It is the 3403rd prime; the next prime is 31649 and the one before is 31627.
- 3
The divisors add up to 31644; without 31643 itself that is 1, so 31643 is deficient (1 is less than 31643). Euler's totient φ(31643) = 31642 numbers up to 31643 share no factor with it.
- 4
The digits of 31643 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 41 steps to reach 1.
31643 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 31644 |
| Euler totient φ(n) | 31642 |
| Square | 1001279449 |
| Cube | 31683485604707 |
| Square root | 177.884794 |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 41 |
| Scientific notation | 3.1643 × |
31643 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand six hundred and forty-three |
| Binary (base 2) | 111101110011011 |
| Octal (base 8) | 75633 |
| Hexadecimal (base 16) | 7B9B |
| Base 3 | 1121101222 |
| As time | 31643 seconds = 8 h 47 min 23 s |
Is 31643 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 2) | 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 5) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | 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 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31643 a prime number?
Yes. 31643 is divisible only by 1 and itself.
What are the factors of 31643?
1, 31643.
What is 31643 in binary?
111101110011011 (hexadecimal 7B9B, octal 75633).
What is the square root of 31643?
About 177.8848.
Is 31643 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 31643?
31643 is the 3403rd prime number.