The number 47145
47145 is a composite number with 16 divisors. Its prime factorisation is 3 × 5 × 7 × 449. Divisors (16): 1, 3, 5, 7, 15, 21, 35, 105, 449, 1347, 2245, 3143, 6735, 9429, 15715, 47145.
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How to work it out
- 1
What is special about 47145: a Harshad number: divisible by its digit sum 21.
- 2
47145 is composite. Its prime factorisation is
- 3
The divisors add up to 86400; without 47145 itself that is 39255, so 47145 is deficient (39255 is less than 47145). Euler's totient φ(47145) = 21504 numbers up to 47145 share no factor with it.
- 4
The digits of 47145 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 83 steps to reach 1.
LaTeX source of the formulas on this page
\[ 47145 = 3 \times 5 \times 7 \times 449 \]
47145 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 86400 |
| Euler totient φ(n) | 21504 |
| Square | 2222651025 |
| Cube | 104786882573625 |
| Square root | 217.128994 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 83 |
| Scientific notation | 4.7145 × |
47145 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand one hundred and forty-five |
| Binary (base 2) | 1011100000101001 |
| Octal (base 8) | 134051 |
| Hexadecimal (base 16) | B829 |
| Base 3 | 2101200010 |
| As time | 47145 seconds = 13 h 5 min 45 s |
Is 47145 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 | Yes (47145 ÷ 3 = 15715) | 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 | Yes (47145 ÷ 5 = 9429) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (47145 ÷ 7 = 6735) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 47145 a prime number?
No. 47145 = 3 × 5 × 7 × 449, so it is divisible by 3.
What are the factors of 47145?
1, 3, 5, 7, 15, 21, 35, 105, 449, 1347, 2245, 3143, 6735, 9429, 15715, 47145.
What is 47145 in binary?
1011100000101001 (hexadecimal B829, octal 134051).
What is the square root of 47145?
About 217.1290.
Is 47145 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 47145?
47145 is a Harshad number: divisible by its digit sum 21.