The number 7749
7749 is a composite number with 16 divisors. Its prime factorisation is × 7 × 41. Divisors (16): 1, 3, 7, 9, 21, 27, 41, 63, 123, 189, 287, 369, 861, 1107, 2583, 7749.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 7749: a Harshad number: divisible by its digit sum 27.
- 2
7749 is composite. Its prime factorisation is
- 3
The divisors add up to 13440; without 7749 itself that is 5691, so 7749 is deficient (5691 is less than 7749). Euler's totient φ(7749) = 4320 numbers up to 7749 share no factor with it.
- 4
The digits of 7749 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 52 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7749 = 3^{3} \times 7 \times 41 \]7749 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 13440 |
| Euler totient φ(n) | 4320 |
| Square | 60047001 |
| Cube | 465304210749 |
| Square root | 88.028405 (= 3√861) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 52 |
| Scientific notation | 7.749 × |
7749 in other forms
| Form | Value |
|---|---|
| In words | seven thousand seven hundred and forty-nine |
| Binary (base 2) | 1111001000101 |
| Octal (base 8) | 17105 |
| Hexadecimal (base 16) | 1E45 |
| Base 3 | 101122000 |
| As time | 7749 seconds = 2 h 9 min 9 s |
Is 7749 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 | Yes (7749 ÷ 3 = 2583) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (7749 ÷ 7 = 1107) | 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 | Yes (7749 ÷ 9 = 861) | 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 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 7749 a prime number?
No. 7749 = × 7 × 41, so it is divisible by 3.
What are the factors of 7749?
1, 3, 7, 9, 21, 27, 41, 63, 123, 189, 287, 369, 861, 1107, 2583, 7749.
What is 7749 in binary?
1111001000101 (hexadecimal 1E45, octal 17105).
What is the square root of 7749?
About 88.0284, exactly 3√861.
Is 7749 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 7749?
7749 is a Harshad number: divisible by its digit sum 27.