The number 49991
49991 is a twin prime (49991 and 49993 are both prime) and the 5131st prime number. Its only divisors are 1 and 49991.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 49991: a twin prime (49991 and 49993 are both prime); the 5131st prime number.
- 2
49991 is prime, so its only factors are 1 and 49991. It is the 5131st prime; the next prime is 49993 and the one before is 49957.
- 3
The divisors add up to 49992; without 49991 itself that is 1, so 49991 is deficient (1 is less than 49991). Euler's totient φ(49991) = 49990 numbers up to 49991 share no factor with it.
- 4
The digits of 49991 add up to 32, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 88 steps to reach 1.
49991 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 49992 |
| Euler totient φ(n) | 49990 |
| Square | 2499100081 |
| Cube | 124932512149271 |
| Square root | 223.586672 |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 88 |
| Scientific notation | 4.9991 × |
49991 in other forms
| Form | Value |
|---|---|
| In words | forty-nine thousand nine hundred and ninety-one |
| Binary (base 2) | 1100001101000111 |
| Octal (base 8) | 141507 |
| Hexadecimal (base 16) | C347 |
| Base 3 | 2112120112 |
| As time | 49991 seconds = 13 h 53 min 11 s |
Is 49991 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 1) | 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 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 7) | 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 1) | 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 49991 a prime number?
Yes. 49991 is divisible only by 1 and itself.
What are the factors of 49991?
1, 49991.
What is 49991 in binary?
1100001101000111 (hexadecimal C347, octal 141507).
What is the square root of 49991?
About 223.5867.
Is 49991 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 49991?
49991 is a twin prime (49991 and 49993 are both prime); the 5131st prime number.