The number 320
320 is a composite number with 14 divisors. Its prime factorisation is × 5. Divisors (14): 1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 160, 320.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 320: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 5.
- 2
320 is composite. Its prime factorisation is
- 3
The divisors add up to 762; without 320 itself that is 442, so 320 is abundant (442 is more than 320). Euler's totient φ(320) = 128 numbers up to 320 share no factor with it.
- 4
The digits of 320 add up to 5, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 11 steps to reach 1.
LaTeX source of the formulas on this page
\[ 320 = 2^{6} \times 5 \]320 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 14 |
| Sum of divisors | 762 |
| Euler totient φ(n) | 128 |
| Square | 102400 |
| Cube | 32768000 |
| Square root | 17.888544 (= 8√5) |
| Digit sum / digital root | 5 / 5 |
| Collatz steps to 1 | 11 |
| Scientific notation | 3.2 × |
320 in other forms
| Form | Value |
|---|---|
| In words | three hundred and twenty |
| Roman numerals | CCCXX |
| Binary (base 2) | 101000000 |
| Octal (base 8) | 500 |
| Hexadecimal (base 16) | 140 |
| Base 3 | 102212 |
| As time | 320 seconds = 5 min 20 s |
Is 320 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (320 ÷ 2 = 160) | 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 (320 ÷ 4 = 80) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (320 ÷ 5 = 64) | 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 5) | 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 (320 ÷ 8 = 40) | 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 (320 ÷ 10 = 32) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | 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 320 a prime number?
No. 320 = × 5, so it is divisible by 2.
What are the factors of 320?
1, 2, 4, 5, 8, 10, 16, 20, 32, 40, 64, 80, 160, 320.
What is 320 in binary?
101000000 (hexadecimal 140, octal 500).
What is the square root of 320?
About 17.8885, exactly 8√5.
What is 320 in Roman numerals?
CCCXX.
Is 320 divisible by 3?
No. Its digits add up to 5, which is not a multiple of 3.
What is special about the number 320?
320 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 5.