The number 80020
80020 is a composite number with 12 divisors. Its prime factorisation is × 5 × 4001. Divisors (12): 1, 2, 4, 5, 10, 20, 4001, 8002, 16004, 20005, 40010, 80020.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 80020: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 10.
- 2
80020 is composite. Its prime factorisation is
- 3
The divisors add up to 168084; without 80020 itself that is 88064, so 80020 is abundant (88064 is more than 80020). Euler's totient φ(80020) = 32000 numbers up to 80020 share no factor with it.
- 4
The digits of 80020 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 68 steps to reach 1.
LaTeX source of the formulas on this page
\[ 80020 = 2^{2} \times 5 \times 4001 \]80020 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 168084 |
| Euler totient φ(n) | 32000 |
| Square | 6403200400 |
| Cube | 512384096008000 |
| Square root | 282.878066 (= 2√20005) |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 68 |
| Scientific notation | 8.002 × |
80020 in other forms
| Form | Value |
|---|---|
| In words | eighty thousand and twenty |
| Binary (base 2) | 10011100010010100 |
| Octal (base 8) | 234224 |
| Hexadecimal (base 16) | 13894 |
| Base 3 | 11001202201 |
| As time | 80020 seconds = 22 h 13 min 40 s |
Is 80020 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (80020 ÷ 2 = 40010) | 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 (80020 ÷ 4 = 20005) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (80020 ÷ 5 = 16004) | 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 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 | No (remainder 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (80020 ÷ 10 = 8002) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | 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 80020 a prime number?
No. 80020 = × 5 × 4001, so it is divisible by 2.
What are the factors of 80020?
1, 2, 4, 5, 10, 20, 4001, 8002, 16004, 20005, 40010, 80020.
What is 80020 in binary?
10011100010010100 (hexadecimal 13894, octal 234224).
What is the square root of 80020?
About 282.8781, exactly 2√20005.
Is 80020 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 80020?
80020 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 10.