The number 87989
87989 is a composite number with 8 divisors. Its prime factorisation is 11 × 19 × 421. Divisors (8): 1, 11, 19, 209, 421, 4631, 7999, 87989.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
87989 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
87989 is composite. Its prime factorisation is
- 3
The divisors add up to 101280; without 87989 itself that is 13291, so 87989 is deficient (13291 is less than 87989). Euler's totient φ(87989) = 75600 numbers up to 87989 share no factor with it.
- 4
The digits of 87989 add up to 41, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 71 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87989 = 11 \times 19 \times 421 \]
87989 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 101280 |
| Euler totient φ(n) | 75600 |
| Square | 7742064121 |
| Cube | 681216479942669 |
| Square root | 296.629398 |
| Digit sum / digital root | 41 / 5 |
| Collatz steps to 1 | 71 |
| Scientific notation | 8.7989 × |
87989 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand nine hundred and eighty-nine |
| Binary (base 2) | 10101011110110101 |
| Octal (base 8) | 253665 |
| Hexadecimal (base 16) | 157B5 |
| Base 3 | 11110200212 |
| As time | 87989 seconds = 24 h 26 min 29 s |
Is 87989 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 2) | 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 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 5) | 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 | Yes (87989 ÷ 11 = 7999) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 87989 a prime number?
No. 87989 = 11 × 19 × 421, so it is divisible by 11.
What are the factors of 87989?
1, 11, 19, 209, 421, 4631, 7999, 87989.
What is 87989 in binary?
10101011110110101 (hexadecimal 157B5, octal 253665).
What is the square root of 87989?
About 296.6294.
Is 87989 divisible by 3?
No. Its digits add up to 41, which is not a multiple of 3.
What is special about the number 87989?
It is a composite number with 8 divisors.