The number 7890
7890 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 5 × 263. Divisors (16): 1, 2, 3, 5, 6, 10, 15, 30, 263, 526, 789, 1315, 1578, 2630, 3945, 7890.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
7890 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
7890 is composite. Its prime factorisation is
- 3
The divisors add up to 19008; without 7890 itself that is 11118, so 7890 is abundant (11118 is more than 7890). Euler's totient φ(7890) = 2096 numbers up to 7890 share no factor with it.
- 4
The digits of 7890 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 101 steps to reach 1.
LaTeX source of the formulas on this page
\[ 7890 = 2 \times 3 \times 5 \times 263 \]
7890 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 19008 |
| Euler totient φ(n) | 2096 |
| Square | 62252100 |
| Cube | 491169069000 |
| Square root | 88.825672 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 101 |
| Scientific notation | 7.89 × |
7890 in other forms
| Form | Value |
|---|---|
| In words | seven thousand eight hundred and ninety |
| Binary (base 2) | 1111011010010 |
| Octal (base 8) | 17322 |
| Hexadecimal (base 16) | 1ED2 |
| Base 3 | 101211020 |
| As time | 7890 seconds = 2 h 11 min 30 s |
Is 7890 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (7890 ÷ 2 = 3945) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (7890 ÷ 3 = 2630) | 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 (7890 ÷ 5 = 1578) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (7890 ÷ 6 = 1315) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 2) | 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 (7890 ÷ 10 = 789) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | 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 7890 a prime number?
No. 7890 = 2 × 3 × 5 × 263, so it is divisible by 2.
What are the factors of 7890?
1, 2, 3, 5, 6, 10, 15, 30, 263, 526, 789, 1315, 1578, 2630, 3945, 7890.
What is 7890 in binary?
1111011010010 (hexadecimal 1ED2, octal 17322).
What is the square root of 7890?
About 88.8257.
Is 7890 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 7890?
It is a composite number with 16 divisors.