The number 84021
84021 is a composite number with 8 divisors. Its prime factorisation is 3 × 7 × 4001. Divisors (8): 1, 3, 7, 21, 4001, 12003, 28007, 84021.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
84021 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
84021 is composite. Its prime factorisation is
- 3
The divisors add up to 128064; without 84021 itself that is 44043, so 84021 is deficient (44043 is less than 84021). Euler's totient φ(84021) = 48000 numbers up to 84021 share no factor with it.
- 4
The digits of 84021 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 32 steps to reach 1.
LaTeX source of the formulas on this page
\[ 84021 = 3 \times 7 \times 4001 \]
84021 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 128064 |
| Euler totient φ(n) | 48000 |
| Square | 7059528441 |
| Cube | 593148639141261 |
| Square root | 289.863761 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 32 |
| Scientific notation | 8.4021 × |
84021 in other forms
| Form | Value |
|---|---|
| In words | eighty-four thousand and twenty-one |
| Binary (base 2) | 10100100000110101 |
| Octal (base 8) | 244065 |
| Hexadecimal (base 16) | 14835 |
| Base 3 | 11021020220 |
| As time | 84021 seconds = 23 h 20 min 21 s |
Is 84021 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 | Yes (84021 ÷ 3 = 28007) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (84021 ÷ 7 = 12003) | 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 6) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 84021 a prime number?
No. 84021 = 3 × 7 × 4001, so it is divisible by 3.
What are the factors of 84021?
1, 3, 7, 21, 4001, 12003, 28007, 84021.
What is 84021 in binary?
10100100000110101 (hexadecimal 14835, octal 244065).
What is the square root of 84021?
About 289.8638.
Is 84021 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 84021?
It is a composite number with 8 divisors.