The number 78800
78800 is a composite number with 30 divisors. Its prime factorisation is × × 197. Divisors (30): 1, 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100, 197, 200, 394 … 78800.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
78800 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
78800 is composite. Its prime factorisation is
- 3
The divisors add up to 190278; without 78800 itself that is 111478, so 78800 is abundant (111478 is more than 78800). Euler's totient φ(78800) = 31360 numbers up to 78800 share no factor with it.
- 4
The digits of 78800 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 76 steps to reach 1.
LaTeX source of the formulas on this page
\[ 78800 = 2^{4} \times 5^{2} \times 197 \]78800 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 30 |
| Sum of divisors | 190278 |
| Euler totient φ(n) | 31360 |
| Square | 6209440000 |
| Cube | 489303872000000 |
| Square root | 280.713377 (= 20√197) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 76 |
| Scientific notation | 7.88 × |
78800 in other forms
| Form | Value |
|---|---|
| In words | seventy-eight thousand eight hundred |
| Binary (base 2) | 10011001111010000 |
| Octal (base 8) | 231720 |
| Hexadecimal (base 16) | 133D0 |
| Base 3 | 11000002112 |
| As time | 78800 seconds = 21 h 53 min 20 s |
Is 78800 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (78800 ÷ 2 = 39400) | 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 (78800 ÷ 4 = 19700) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (78800 ÷ 5 = 15760) | 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 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 | Yes (78800 ÷ 8 = 9850) | 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 | Yes (78800 ÷ 10 = 7880) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | 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 78800 a prime number?
No. 78800 = × × 197, so it is divisible by 2.
What are the factors of 78800?
1, 2, 4, 5, 8, 10, 16, 20, 25, 40, 50, 80, 100, 197, 200, 394, 400, 788, 985, 1576, 1970, 3152, 3940, 4925, 7880, 9850, 15760, 19700, 39400, 78800.
What is 78800 in binary?
10011001111010000 (hexadecimal 133D0, octal 231720).
What is the square root of 78800?
About 280.7134, exactly 20√197.
Is 78800 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 78800?
It is a composite number with 30 divisors.