The number 42129
42129 is a composite number with 12 divisors. Its prime factorisation is × 31 × 151. Divisors (12): 1, 3, 9, 31, 93, 151, 279, 453, 1359, 4681, 14043, 42129.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42129 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42129 is composite. Its prime factorisation is
- 3
The divisors add up to 63232; without 42129 itself that is 21103, so 42129 is deficient (21103 is less than 42129). Euler's totient φ(42129) = 27000 numbers up to 42129 share no factor with it.
- 4
The digits of 42129 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 106 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42129 = 3^{2} \times 31 \times 151 \]42129 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 63232 |
| Euler totient φ(n) | 27000 |
| Square | 1774852641 |
| Cube | 74772766912689 |
| Square root | 205.253502 (= 3√4681) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 106 |
| Scientific notation | 4.2129 × |
42129 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand one hundred and twenty-nine |
| Binary (base 2) | 1010010010010001 |
| Octal (base 8) | 122221 |
| Hexadecimal (base 16) | A491 |
| Base 3 | 2010210100 |
| As time | 42129 seconds = 11 h 42 min 9 s |
Is 42129 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 (42129 ÷ 3 = 14043) | 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 | No (remainder 4) | 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 | No (remainder 3) | 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 | Yes (42129 ÷ 9 = 4681) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | 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 42129 a prime number?
No. 42129 = × 31 × 151, so it is divisible by 3.
What are the factors of 42129?
1, 3, 9, 31, 93, 151, 279, 453, 1359, 4681, 14043, 42129.
What is 42129 in binary?
1010010010010001 (hexadecimal A491, octal 122221).
What is the square root of 42129?
About 205.2535, exactly 3√4681.
Is 42129 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 42129?
It is a composite number with 12 divisors.