The number 42981
42981 is a binary palindrome (1010011111100101). Its prime factorisation is 3 × 14327. Divisors (4): 1, 3, 14327, 42981.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42981: a binary palindrome (1010011111100101); a semiprime: 3 × 14327, the product of two primes.
- 2
42981 is composite. Its prime factorisation is
- 3
The divisors add up to 57312; without 42981 itself that is 14331, so 42981 is deficient (14331 is less than 42981). Euler's totient φ(42981) = 28652 numbers up to 42981 share no factor with it.
- 4
The digits of 42981 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 57 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42981 = 3 \times 14327 \]
42981 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 57312 |
| Euler totient φ(n) | 28652 |
| Square | 1847366361 |
| Cube | 79401653562141 |
| Square root | 207.318595 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 57 |
| Scientific notation | 4.2981 × |
42981 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand nine hundred and eighty-one |
| Binary (base 2) | 1010011111100101 |
| Octal (base 8) | 123745 |
| Hexadecimal (base 16) | A7E5 |
| Base 3 | 2011221220 |
| As time | 42981 seconds = 11 h 56 min 21 s |
Is 42981 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 (42981 ÷ 3 = 14327) | 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 1) | 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 1) | 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 5) | 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 | No (remainder 1) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42981 a prime number?
No. 42981 = 3 × 14327, so it is divisible by 3.
What are the factors of 42981?
1, 3, 14327, 42981.
What is 42981 in binary?
1010011111100101 (hexadecimal A7E5, octal 123745).
What is the square root of 42981?
About 207.3186.
Is 42981 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 42981?
42981 is a binary palindrome (1010011111100101); a semiprime: 3 × 14327, the product of two primes.