The number 80720
80720 is a composite number with 20 divisors. Its prime factorisation is × 5 × 1009. Divisors (20): 1, 2, 4, 5, 8, 10, 16, 20, 40, 80, 1009, 2018, 4036, 5045, 8072, 10090 … 80720.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
80720 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
80720 is composite. Its prime factorisation is
- 3
The divisors add up to 187860; without 80720 itself that is 107140, so 80720 is abundant (107140 is more than 80720). Euler's totient φ(80720) = 32256 numbers up to 80720 share no factor with it.
- 4
The digits of 80720 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 45 steps to reach 1.
LaTeX source of the formulas on this page
\[ 80720 = 2^{4} \times 5 \times 1009 \]80720 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 187860 |
| Euler totient φ(n) | 32256 |
| Square | 6515718400 |
| Cube | 525948789248000 |
| Square root | 284.112654 (= 4√5045) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 45 |
| Scientific notation | 8.072 × |
80720 in other forms
| Form | Value |
|---|---|
| In words | eighty thousand seven hundred and twenty |
| Binary (base 2) | 10011101101010000 |
| Octal (base 8) | 235520 |
| Hexadecimal (base 16) | 13B50 |
| Base 3 | 11002201122 |
| As time | 80720 seconds = 22 h 25 min 20 s |
Is 80720 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (80720 ÷ 2 = 40360) | 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 (80720 ÷ 4 = 20180) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (80720 ÷ 5 = 16144) | 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 3) | 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 (80720 ÷ 8 = 10090) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (80720 ÷ 10 = 8072) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | 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 80720 a prime number?
No. 80720 = × 5 × 1009, so it is divisible by 2.
What are the factors of 80720?
1, 2, 4, 5, 8, 10, 16, 20, 40, 80, 1009, 2018, 4036, 5045, 8072, 10090, 16144, 20180, 40360, 80720.
What is 80720 in binary?
10011101101010000 (hexadecimal 13B50, octal 235520).
What is the square root of 80720?
About 284.1127, exactly 4√5045.
Is 80720 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 80720?
It is a composite number with 20 divisors.