The number 87421
87421 is the 8486th prime number. Its only divisors are 1 and 87421.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 87421: the 8486th prime number.
- 2
87421 is prime, so its only factors are 1 and 87421. It is the 8486th prime; the next prime is 87427 and the one before is 87407.
- 3
The divisors add up to 87422; without 87421 itself that is 1, so 87421 is deficient (1 is less than 87421). Euler's totient φ(87421) = 87420 numbers up to 87421 share no factor with it.
- 4
The digits of 87421 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 58 steps to reach 1.
87421 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 87422 |
| Euler totient φ(n) | 87420 |
| Square | 7642431241 |
| Cube | 668108981519461 |
| Square root | 295.670425 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 58 |
| Scientific notation | 8.7421 × |
87421 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand four hundred and twenty-one |
| Binary (base 2) | 10101010101111101 |
| Octal (base 8) | 252575 |
| Hexadecimal (base 16) | 1557D |
| Base 3 | 11102220211 |
| As time | 87421 seconds = 24 h 17 min 1 s |
Is 87421 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 5) | 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 4) | 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 4) | 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 87421 a prime number?
Yes. 87421 is divisible only by 1 and itself.
What are the factors of 87421?
1, 87421.
What is 87421 in binary?
10101010101111101 (hexadecimal 1557D, octal 252575).
What is the square root of 87421?
About 295.6704.
Is 87421 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 87421?
87421 is the 8486th prime number.