The number 87021
87021 is a composite number with 16 divisors. Its prime factorisation is × 11 × 293. Divisors (16): 1, 3, 9, 11, 27, 33, 99, 293, 297, 879, 2637, 3223, 7911, 9669, 29007, 87021.
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How to work it out
- 1
87021 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
87021 is composite. Its prime factorisation is
- 3
The divisors add up to 141120; without 87021 itself that is 54099, so 87021 is deficient (54099 is less than 87021). Euler's totient φ(87021) = 52560 numbers up to 87021 share no factor with it.
- 4
The digits of 87021 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 164 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87021 = 3^{3} \times 11 \times 293 \]87021 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 141120 |
| Euler totient φ(n) | 52560 |
| Square | 7572654441 |
| Cube | 658979962110261 |
| Square root | 294.993220 (= 3√9669) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 164 |
| Scientific notation | 8.7021 × |
87021 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand and twenty-one |
| Binary (base 2) | 10101001111101101 |
| Octal (base 8) | 251755 |
| Hexadecimal (base 16) | 153ED |
| Base 3 | 11102101000 |
| As time | 87021 seconds = 24 h 10 min 21 s |
Is 87021 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 (87021 ÷ 3 = 29007) | 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 | 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 | Yes (87021 ÷ 9 = 9669) | 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 | Yes (87021 ÷ 11 = 7911) | 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 87021 a prime number?
No. 87021 = × 11 × 293, so it is divisible by 3.
What are the factors of 87021?
1, 3, 9, 11, 27, 33, 99, 293, 297, 879, 2637, 3223, 7911, 9669, 29007, 87021.
What is 87021 in binary?
10101001111101101 (hexadecimal 153ED, octal 251755).
What is the square root of 87021?
About 294.9932, exactly 3√9669.
Is 87021 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 87021?
It is a composite number with 16 divisors.