The number 78320
78320 is a composite number with 40 divisors. Its prime factorisation is × 5 × 11 × 89. Divisors (40): 1, 2, 4, 5, 8, 10, 11, 16, 20, 22, 40, 44, 55, 80, 88, 89 … 78320.
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How to work it out
- 1
What is special about 78320: a Harshad number: divisible by its digit sum 20.
- 2
78320 is composite. Its prime factorisation is
- 3
The divisors add up to 200880; without 78320 itself that is 122560, so 78320 is abundant (122560 is more than 78320). Euler's totient φ(78320) = 28160 numbers up to 78320 share no factor with it.
- 4
The digits of 78320 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 76 steps to reach 1.
LaTeX source of the formulas on this page
\[ 78320 = 2^{4} \times 5 \times 11 \times 89 \]78320 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 40 |
| Sum of divisors | 200880 |
| Euler totient φ(n) | 28160 |
| Square | 6134022400 |
| Cube | 480416634368000 |
| Square root | 279.857106 (= 4√4895) |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 76 |
| Scientific notation | 7.832 × |
78320 in other forms
| Form | Value |
|---|---|
| In words | seventy-eight thousand three hundred and twenty |
| Binary (base 2) | 10011000111110000 |
| Octal (base 8) | 230760 |
| Hexadecimal (base 16) | 131F0 |
| Base 3 | 10222102202 |
| As time | 78320 seconds = 21 h 45 min 20 s |
Is 78320 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (78320 ÷ 2 = 39160) | 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 (78320 ÷ 4 = 19580) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (78320 ÷ 5 = 15664) | 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 4) | 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 (78320 ÷ 8 = 9790) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (78320 ÷ 10 = 7832) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (78320 ÷ 11 = 7120) | 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 78320 a prime number?
No. 78320 = × 5 × 11 × 89, so it is divisible by 2.
What are the factors of 78320?
1, 2, 4, 5, 8, 10, 11, 16, 20, 22, 40, 44, 55, 80, 88, 89, 110, 176, 178, 220, 356, 440, 445, 712, 880, 890, 979, 1424, 1780, 1958, 3560, 3916, 4895, 7120, 7832, 9790, 15664, 19580, 39160, 78320.
What is 78320 in binary?
10011000111110000 (hexadecimal 131F0, octal 230760).
What is the square root of 78320?
About 279.8571, exactly 4√4895.
Is 78320 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 78320?
78320 is a Harshad number: divisible by its digit sum 20.