The number 6390
6390 is a composite number with 24 divisors. Its prime factorisation is 2 × × 5 × 71. Divisors (24): 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 71, 90, 142, 213, 355 … 6390.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 6390: a Harshad number: divisible by its digit sum 18.
- 2
6390 is composite. Its prime factorisation is
- 3
The divisors add up to 16848; without 6390 itself that is 10458, so 6390 is abundant (10458 is more than 6390). Euler's totient φ(6390) = 1680 numbers up to 6390 share no factor with it.
- 4
The digits of 6390 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 75 steps to reach 1.
LaTeX source of the formulas on this page
\[ 6390 = 2 \times 3^{2} \times 5 \times 71 \]6390 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 16848 |
| Euler totient φ(n) | 1680 |
| Square | 40832100 |
| Cube | 260917119000 |
| Square root | 79.937476 (= 3√710) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 75 |
| Scientific notation | 6.39 × |
6390 in other forms
| Form | Value |
|---|---|
| In words | six thousand three hundred and ninety |
| Binary (base 2) | 1100011110110 |
| Octal (base 8) | 14366 |
| Hexadecimal (base 16) | 18F6 |
| Base 3 | 22202200 |
| As time | 6390 seconds = 1 h 46 min 30 s |
Is 6390 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (6390 ÷ 2 = 3195) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (6390 ÷ 3 = 2130) | 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 (6390 ÷ 5 = 1278) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (6390 ÷ 6 = 1065) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (6390 ÷ 9 = 710) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (6390 ÷ 10 = 639) | 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 6390 a prime number?
No. 6390 = 2 × × 5 × 71, so it is divisible by 2.
What are the factors of 6390?
1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 71, 90, 142, 213, 355, 426, 639, 710, 1065, 1278, 2130, 3195, 6390.
What is 6390 in binary?
1100011110110 (hexadecimal 18F6, octal 14366).
What is the square root of 6390?
About 79.9375, exactly 3√710.
Is 6390 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 6390?
6390 is a Harshad number: divisible by its digit sum 18.