The number 85021
85021 is the 8279th prime number. Its only divisors are 1 and 85021.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 85021: the 8279th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
85021 is prime, so its only factors are 1 and 85021. It is the 8279th prime; the next prime is 85027 and the one before is 85009.
- 3
The divisors add up to 85022; without 85021 itself that is 1, so 85021 is deficient (1 is less than 85021). Euler's totient φ(85021) = 85020 numbers up to 85021 share no factor with it.
- 4
The digits of 85021 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 151 steps to reach 1.
85021 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 85022 |
| Euler totient φ(n) | 85020 |
| Square | 7228570441 |
| Cube | 614580287464261 |
| Square root | 291.583607 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 151 |
| Scientific notation | 8.5021 × |
85021 in other forms
| Form | Value |
|---|---|
| In words | eighty-five thousand and twenty-one |
| Binary (base 2) | 10100110000011101 |
| Octal (base 8) | 246035 |
| Hexadecimal (base 16) | 14C1D |
| Base 3 | 11022121221 |
| As time | 85021 seconds = 23 h 37 min 1 s |
Is 85021 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 1) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 7) | 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 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 85021 a prime number?
Yes. 85021 is divisible only by 1 and itself.
What are the factors of 85021?
1, 85021.
What is 85021 in binary?
10100110000011101 (hexadecimal 14C1D, octal 246035).
What is the square root of 85021?
About 291.5836.
Is 85021 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 85021?
85021 is the 8279th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.