The number 77828
77828 is a composite number with 6 divisors. Its prime factorisation is × 19457. Divisors (6): 1, 2, 4, 19457, 38914, 77828.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 77828: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
77828 is composite. Its prime factorisation is
- 3
The divisors add up to 136206; without 77828 itself that is 58378, so 77828 is deficient (58378 is less than 77828). Euler's totient φ(77828) = 38912 numbers up to 77828 share no factor with it.
- 4
The digits of 77828 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 50 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77828 = 2^{2} \times 19457 \]77828 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 136206 |
| Euler totient φ(n) | 38912 |
| Square | 6057197584 |
| Cube | 471419573567552 |
| Square root | 278.976702 (= 2√19457) |
| Digit sum / digital root | 32 / 5 |
| Collatz steps to 1 | 50 |
| Scientific notation | 7.7828 × |
77828 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand eight hundred and twenty-eight |
| Binary (base 2) | 10011000000000100 |
| Octal (base 8) | 230004 |
| Hexadecimal (base 16) | 13004 |
| Base 3 | 10221202112 |
| As time | 77828 seconds = 21 h 37 min 8 s |
Is 77828 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (77828 ÷ 2 = 38914) | 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 | Yes (77828 ÷ 4 = 19457) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 4) | 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 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77828 a prime number?
No. 77828 = × 19457, so it is divisible by 2.
What are the factors of 77828?
1, 2, 4, 19457, 38914, 77828.
What is 77828 in binary?
10011000000000100 (hexadecimal 13004, octal 230004).
What is the square root of 77828?
About 278.9767, exactly 2√19457.
Is 77828 divisible by 3?
No. Its digits add up to 32, which is not a multiple of 3.
What is special about the number 77828?
77828 is a happy number: repeatedly adding the squares of its digits reaches 1.