The number 12390
12390 is a composite number with 32 divisors. Its prime factorisation is 2 × 3 × 5 × 7 × 59. Divisors (32): 1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 59, 70, 105 … 12390.
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How to work it out
- 1
What is special about 12390: a Harshad number: divisible by its digit sum 15.
- 2
12390 is composite. Its prime factorisation is
- 3
The divisors add up to 34560; without 12390 itself that is 22170, so 12390 is abundant (22170 is more than 12390). Euler's totient φ(12390) = 2784 numbers up to 12390 share no factor with it.
- 4
The digits of 12390 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 187 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12390 = 2 \times 3 \times 5 \times 7 \times 59 \]
12390 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 34560 |
| Euler totient φ(n) | 2784 |
| Square | 153512100 |
| Cube | 1902014919000 |
| Square root | 111.310377 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 187 |
| Scientific notation | 1.239 × |
12390 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand three hundred and ninety |
| Binary (base 2) | 11000001100110 |
| Octal (base 8) | 30146 |
| Hexadecimal (base 16) | 3066 |
| Base 3 | 121222220 |
| As time | 12390 seconds = 3 h 26 min 30 s |
Is 12390 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (12390 ÷ 2 = 6195) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (12390 ÷ 3 = 4130) | 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 (12390 ÷ 5 = 2478) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (12390 ÷ 6 = 2065) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (12390 ÷ 7 = 1770) | 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 (12390 ÷ 10 = 1239) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | 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 12390 a prime number?
No. 12390 = 2 × 3 × 5 × 7 × 59, so it is divisible by 2.
What are the factors of 12390?
1, 2, 3, 5, 6, 7, 10, 14, 15, 21, 30, 35, 42, 59, 70, 105, 118, 177, 210, 295, 354, 413, 590, 826, 885, 1239, 1770, 2065, 2478, 4130, 6195, 12390.
What is 12390 in binary?
11000001100110 (hexadecimal 3066, octal 30146).
What is the square root of 12390?
About 111.3104.
Is 12390 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 12390?
12390 is a Harshad number: divisible by its digit sum 15.