The number 15749
15749 is the 1837th prime number. Its only divisors are 1 and 15749.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 15749: the 1837th prime number.
- 2
15749 is prime, so its only factors are 1 and 15749. It is the 1837th prime; the next prime is 15761 and the one before is 15739.
- 3
The divisors add up to 15750; without 15749 itself that is 1, so 15749 is deficient (1 is less than 15749). Euler's totient φ(15749) = 15748 numbers up to 15749 share no factor with it.
- 4
The digits of 15749 add up to 26, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 128 steps to reach 1.
15749 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 15750 |
| Euler totient φ(n) | 15748 |
| Square | 248031001 |
| Cube | 3906240234749 |
| Square root | 125.495020 |
| Digit sum / digital root | 26 / 8 |
| Collatz steps to 1 | 128 |
| Scientific notation | 1.5749 × |
15749 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand seven hundred and forty-nine |
| Binary (base 2) | 11110110000101 |
| Octal (base 8) | 36605 |
| Hexadecimal (base 16) | 3D85 |
| Base 3 | 210121022 |
| As time | 15749 seconds = 4 h 22 min 29 s |
Is 15749 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 6) | 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 8) | 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 8) | 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 15749 a prime number?
Yes. 15749 is divisible only by 1 and itself.
What are the factors of 15749?
1, 15749.
What is 15749 in binary?
11110110000101 (hexadecimal 3D85, octal 36605).
What is the square root of 15749?
About 125.4950.
Is 15749 divisible by 3?
No. Its digits add up to 26, which is not a multiple of 3.
What is special about the number 15749?
15749 is the 1837th prime number.