The number 31649
31649 is the 3404th prime number. Its only divisors are 1 and 31649.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31649: the 3404th prime number.
- 2
31649 is prime, so its only factors are 1 and 31649. It is the 3404th prime; the next prime is 31657 and the one before is 31643.
- 3
The divisors add up to 31650; without 31649 itself that is 1, so 31649 is deficient (1 is less than 31649). Euler's totient φ(31649) = 31648 numbers up to 31649 share no factor with it.
- 4
The digits of 31649 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 77 steps to reach 1.
31649 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 31650 |
| Euler totient φ(n) | 31648 |
| Square | 1001659201 |
| Cube | 31701512052449 |
| Square root | 177.901658 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 77 |
| Scientific notation | 3.1649 × |
31649 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand six hundred and forty-nine |
| Binary (base 2) | 111101110100001 |
| Octal (base 8) | 75641 |
| Hexadecimal (base 16) | 7BA1 |
| Base 3 | 1121102012 |
| As time | 31649 seconds = 8 h 47 min 29 s |
Is 31649 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 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | 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 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31649 a prime number?
Yes. 31649 is divisible only by 1 and itself.
What are the factors of 31649?
1, 31649.
What is 31649 in binary?
111101110100001 (hexadecimal 7BA1, octal 75641).
What is the square root of 31649?
About 177.9017.
Is 31649 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 31649?
31649 is the 3404th prime number.