The number 87999
87999 is a composite number with 4 divisors. Its prime factorisation is 3 × 29333. Divisors (4): 1, 3, 29333, 87999.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 87999: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 29333, the product of two primes.
- 2
87999 is composite. Its prime factorisation is
- 3
The divisors add up to 117336; without 87999 itself that is 29337, so 87999 is deficient (29337 is less than 87999). Euler's totient φ(87999) = 58664 numbers up to 87999 share no factor with it.
- 4
The digits of 87999 add up to 42, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 270 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87999 = 3 \times 29333 \]
87999 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 117336 |
| Euler totient φ(n) | 58664 |
| Square | 7743824001 |
| Cube | 681448768263999 |
| Square root | 296.646254 |
| Digit sum / digital root | 42 / 6 |
| Collatz steps to 1 | 270 |
| Scientific notation | 8.7999 × |
87999 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand nine hundred and ninety-nine |
| Binary (base 2) | 10101011110111111 |
| Octal (base 8) | 253677 |
| Hexadecimal (base 16) | 157BF |
| Base 3 | 11110201020 |
| As time | 87999 seconds = 24 h 26 min 39 s |
Is 87999 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 (87999 ÷ 3 = 29333) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | 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 2) | 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 7) | 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 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 87999 a prime number?
No. 87999 = 3 × 29333, so it is divisible by 3.
What are the factors of 87999?
1, 3, 29333, 87999.
What is 87999 in binary?
10101011110111111 (hexadecimal 157BF, octal 253677).
What is the square root of 87999?
About 296.6463.
Is 87999 divisible by 3?
Yes. Its digits add up to 42, a multiple of 3.
What is special about the number 87999?
87999 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 29333, the product of two primes.