The number 78990
78990 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 5 × 2633. Divisors (16): 1, 2, 3, 5, 6, 10, 15, 30, 2633, 5266, 7899, 13165, 15798, 26330, 39495, 78990.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
78990 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
78990 is composite. Its prime factorisation is
- 3
The divisors add up to 189648; without 78990 itself that is 110658, so 78990 is abundant (110658 is more than 78990). Euler's totient φ(78990) = 21056 numbers up to 78990 share no factor with it.
- 4
The digits of 78990 add up to 33, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 63 steps to reach 1.
LaTeX source of the formulas on this page
\[ 78990 = 2 \times 3 \times 5 \times 2633 \]
78990 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 189648 |
| Euler totient φ(n) | 21056 |
| Square | 6239420100 |
| Cube | 492851793699000 |
| Square root | 281.051597 |
| Digit sum / digital root | 33 / 6 |
| Collatz steps to 1 | 63 |
| Scientific notation | 7.899 × |
78990 in other forms
| Form | Value |
|---|---|
| In words | seventy-eight thousand nine hundred and ninety |
| Binary (base 2) | 10011010010001110 |
| Octal (base 8) | 232216 |
| Hexadecimal (base 16) | 1348E |
| Base 3 | 11000100120 |
| As time | 78990 seconds = 21 h 56 min 30 s |
Is 78990 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (78990 ÷ 2 = 39495) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (78990 ÷ 3 = 26330) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (78990 ÷ 5 = 15798) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (78990 ÷ 6 = 13165) | 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 6) | 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 | Yes (78990 ÷ 10 = 7899) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 78990 a prime number?
No. 78990 = 2 × 3 × 5 × 2633, so it is divisible by 2.
What are the factors of 78990?
1, 2, 3, 5, 6, 10, 15, 30, 2633, 5266, 7899, 13165, 15798, 26330, 39495, 78990.
What is 78990 in binary?
10011010010001110 (hexadecimal 1348E, octal 232216).
What is the square root of 78990?
About 281.0516.
Is 78990 divisible by 3?
Yes. Its digits add up to 33, a multiple of 3.
What is special about the number 78990?
It is a composite number with 16 divisors.