The number 77800
77800 is a composite number with 24 divisors. Its prime factorisation is × × 389. Divisors (24): 1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 200, 389, 778, 1556, 1945 … 77800.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
77800 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
77800 is composite. Its prime factorisation is
- 3
The divisors add up to 181350; without 77800 itself that is 103550, so 77800 is abundant (103550 is more than 77800). Euler's totient φ(77800) = 31040 numbers up to 77800 share no factor with it.
- 4
The digits of 77800 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 169 steps to reach 1.
LaTeX source of the formulas on this page
\[ 77800 = 2^{3} \times 5^{2} \times 389 \]77800 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 181350 |
| Euler totient φ(n) | 31040 |
| Square | 6052840000 |
| Cube | 470910952000000 |
| Square root | 278.926514 (= 10√778) |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 169 |
| Scientific notation | 7.78 × |
77800 in other forms
| Form | Value |
|---|---|
| In words | seventy-seven thousand eight hundred |
| Binary (base 2) | 10010111111101000 |
| Octal (base 8) | 227750 |
| Hexadecimal (base 16) | 12FE8 |
| Base 3 | 10221201111 |
| As time | 77800 seconds = 21 h 36 min 40 s |
Is 77800 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (77800 ÷ 2 = 38900) | 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 (77800 ÷ 4 = 19450) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (77800 ÷ 5 = 15560) | 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 | 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 | Yes (77800 ÷ 8 = 9725) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (77800 ÷ 10 = 7780) | 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 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 77800 a prime number?
No. 77800 = × × 389, so it is divisible by 2.
What are the factors of 77800?
1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 200, 389, 778, 1556, 1945, 3112, 3890, 7780, 9725, 15560, 19450, 38900, 77800.
What is 77800 in binary?
10010111111101000 (hexadecimal 12FE8, octal 227750).
What is the square root of 77800?
About 278.9265, exactly 10√778.
Is 77800 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 77800?
It is a composite number with 24 divisors.