The number 77841
77841 is a perfect square (279²). Its prime factorisation is × . Divisors (15): 1, 3, 9, 27, 31, 81, 93, 279, 837, 961, 2511, 2883, 8649, 25947, 77841.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 77841: a perfect square (279²); a Harshad number: divisible by its digit sum 27.
- 2
77841 is composite. Its prime factorisation is
- 3
The divisors add up to 120153; without 77841 itself that is 42312, so 77841 is deficient (42312 is less than 77841). Euler's totient φ(77841) = 50220 numbers up to 77841 share no factor with it.
- 4
The digits of 77841 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 169 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77841 = 3^{4} \times 31^{2} \]77841 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 15 |
| Sum of divisors | 120153 |
| Euler totient φ(n) | 50220 |
| Square | 6059221281 |
| Cube | 471655843734321 |
| Square root | 279 |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.7841 × |
| Perfect power |
77841 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand eight hundred and forty-one |
| Binary (base 2) | 10011000000010001 |
| Octal (base 8) | 230021 |
| Hexadecimal (base 16) | 13011 |
| Base 3 | 10221210000 |
| As time | 77841 seconds = 21 h 37 min 21 s |
Is 77841 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 (77841 ÷ 3 = 25947) | 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 1) | 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 | No (remainder 1) | 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 | Yes (77841 ÷ 9 = 8649) | 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 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 77841 a prime number?
No. 77841 = × , so it is divisible by 3.
What are the factors of 77841?
1, 3, 9, 27, 31, 81, 93, 279, 837, 961, 2511, 2883, 8649, 25947, 77841.
What is 77841 in binary?
10011000000010001 (hexadecimal 13011, octal 230021).
What is the square root of 77841?
279, because 279 × 279 = 77841.
Is 77841 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 77841?
77841 is a perfect square (279²); a Harshad number: divisible by its digit sum 27.