The number 77812
77812 is a composite number with 18 divisors. Its prime factorisation is × × 397. Divisors (18): 1, 2, 4, 7, 14, 28, 49, 98, 196, 397, 794, 1588, 2779, 5558, 11116, 19453 … 77812.
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How to work it out
- 1
What is special about 77812: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
77812 is composite. Its prime factorisation is
- 3
The divisors add up to 158802; without 77812 itself that is 80990, so 77812 is abundant (80990 is more than 77812). Euler's totient φ(77812) = 33264 numbers up to 77812 share no factor with it.
- 4
The digits of 77812 add up to 25, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 94 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77812 = 2^{2} \times 7^{2} \times 397 \]77812 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 18 |
| Sum of divisors | 158802 |
| Euler totient φ(n) | 33264 |
| Square | 6054707344 |
| Cube | 471128887851328 |
| Square root | 278.948024 (= 14√397) |
| Digit sum / digital root | 25 / 7 |
| Collatz steps to 1 | 94 |
| Scientific notation | 7.7812 × |
77812 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand eight hundred and twelve |
| Binary (base 2) | 10010111111110100 |
| Octal (base 8) | 227764 |
| Hexadecimal (base 16) | 12FF4 |
| Base 3 | 10221201221 |
| As time | 77812 seconds = 21 h 36 min 52 s |
Is 77812 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (77812 ÷ 2 = 38906) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (77812 ÷ 4 = 19453) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (77812 ÷ 7 = 11116) | 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 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77812 a prime number?
No. 77812 = × × 397, so it is divisible by 2.
What are the factors of 77812?
1, 2, 4, 7, 14, 28, 49, 98, 196, 397, 794, 1588, 2779, 5558, 11116, 19453, 38906, 77812.
What is 77812 in binary?
10010111111110100 (hexadecimal 12FF4, octal 227764).
What is the square root of 77812?
About 278.9480, exactly 14√397.
Is 77812 divisible by 3?
No. Its digits add up to 25, which is not a multiple of 3.
What is special about the number 77812?
77812 is a happy number: repeatedly adding the squares of its digits reaches 1.