The number 42145
42145 is a composite number with 4 divisors. Its prime factorisation is 5 × 8429. Divisors (4): 1, 5, 8429, 42145.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42145: a semiprime: 5 × 8429, the product of two primes.
- 2
42145 is composite. Its prime factorisation is
- 3
The divisors add up to 50580; without 42145 itself that is 8435, so 42145 is deficient (8435 is less than 42145). Euler's totient φ(42145) = 33712 numbers up to 42145 share no factor with it.
- 4
The digits of 42145 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 88 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42145 = 5 \times 8429 \]
42145 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 50580 |
| Euler totient φ(n) | 33712 |
| Square | 1776201025 |
| Cube | 74857992198625 |
| Square root | 205.292474 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 88 |
| Scientific notation | 4.2145 × |
42145 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand one hundred and forty-five |
| Binary (base 2) | 1010010010100001 |
| Octal (base 8) | 122241 |
| Hexadecimal (base 16) | A4A1 |
| Base 3 | 2010210221 |
| As time | 42145 seconds = 11 h 42 min 25 s |
Is 42145 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 | No (remainder 1) | 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 (42145 ÷ 5 = 8429) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 7) | 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 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42145 a prime number?
No. 42145 = 5 × 8429, so it is divisible by 5.
What are the factors of 42145?
1, 5, 8429, 42145.
What is 42145 in binary?
1010010010100001 (hexadecimal A4A1, octal 122241).
What is the square root of 42145?
About 205.2925.
Is 42145 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 42145?
42145 is a semiprime: 5 × 8429, the product of two primes.