The number 87213
87213 is a composite number with 8 divisors. Its prime factorisation is 3 × 7 × 4153. Divisors (8): 1, 3, 7, 21, 4153, 12459, 29071, 87213.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 87213: a Harshad number: divisible by its digit sum 21.
- 2
87213 is composite. Its prime factorisation is
- 3
The divisors add up to 132928; without 87213 itself that is 45715, so 87213 is deficient (45715 is less than 87213). Euler's totient φ(87213) = 49824 numbers up to 87213 share no factor with it.
- 4
The digits of 87213 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 164 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87213 = 3 \times 7 \times 4153 \]
87213 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 132928 |
| Euler totient φ(n) | 49824 |
| Square | 7606107369 |
| Cube | 663351441972597 |
| Square root | 295.318472 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 164 |
| Scientific notation | 8.7213 × |
87213 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand two hundred and thirteen |
| Binary (base 2) | 10101010010101101 |
| Octal (base 8) | 252255 |
| Hexadecimal (base 16) | 154AD |
| Base 3 | 11102122010 |
| As time | 87213 seconds = 24 h 13 min 33 s |
Is 87213 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 (87213 ÷ 3 = 29071) | 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 3) | 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 (87213 ÷ 7 = 12459) | 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 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | 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 87213 a prime number?
No. 87213 = 3 × 7 × 4153, so it is divisible by 3.
What are the factors of 87213?
1, 3, 7, 21, 4153, 12459, 29071, 87213.
What is 87213 in binary?
10101010010101101 (hexadecimal 154AD, octal 252255).
What is the square root of 87213?
About 295.3185.
Is 87213 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 87213?
87213 is a Harshad number: divisible by its digit sum 21.