The number 80021
80021 is the 7838th prime number. Its only divisors are 1 and 80021.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 80021: the 7838th prime number.
- 2
80021 is prime, so its only factors are 1 and 80021. It is the 7838th prime; the next prime is 80039 and the one before is 79999.
- 3
The divisors add up to 80022; without 80021 itself that is 1, so 80021 is deficient (1 is less than 80021). Euler's totient φ(80021) = 80020 numbers up to 80021 share no factor with it.
- 4
The digits of 80021 add up to 11, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 68 steps to reach 1.
80021 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 80022 |
| Euler totient φ(n) | 80020 |
| Square | 6403360441 |
| Cube | 512403305849261 |
| Square root | 282.879833 |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 68 |
| Scientific notation | 8.0021 × |
80021 in other forms
| Form | Value |
|---|---|
| In words | eighty thousand and twenty-one |
| Binary (base 2) | 10011100010010101 |
| Octal (base 8) | 234225 |
| Hexadecimal (base 16) | 13895 |
| Base 3 | 11001202202 |
| As time | 80021 seconds = 22 h 13 min 41 s |
Is 80021 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | 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 | No (remainder 5) | 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 | No (remainder 1) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 80021 a prime number?
Yes. 80021 is divisible only by 1 and itself.
What are the factors of 80021?
1, 80021.
What is 80021 in binary?
10011100010010101 (hexadecimal 13895, octal 234225).
What is the square root of 80021?
About 282.8798.
Is 80021 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 80021?
80021 is the 7838th prime number.