The number 42121
42121 is a composite number with 4 divisors. Its prime factorisation is 73 × 577. Divisors (4): 1, 73, 577, 42121.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42121: a semiprime: 73 × 577, the product of two primes.
- 2
42121 is composite. Its prime factorisation is
- 3
The divisors add up to 42772; without 42121 itself that is 651, so 42121 is deficient (651 is less than 42121). Euler's totient φ(42121) = 41472 numbers up to 42121 share no factor with it.
- 4
The digits of 42121 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 88 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42121 = 73 \times 577 \]
42121 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 42772 |
| Euler totient φ(n) | 41472 |
| Square | 1774178641 |
| Cube | 74730178537561 |
| Square root | 205.234013 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 88 |
| Scientific notation | 4.2121 × |
42121 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand one hundred and twenty-one |
| Binary (base 2) | 1010010010001001 |
| Octal (base 8) | 122211 |
| Hexadecimal (base 16) | A489 |
| Base 3 | 2010210001 |
| As time | 42121 seconds = 11 h 42 min 1 s |
Is 42121 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 | No (remainder 1) | 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 2) | 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 1) | 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 2) | 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 42121 a prime number?
No. 42121 = 73 × 577, so it is divisible by 73.
What are the factors of 42121?
1, 73, 577, 42121.
What is 42121 in binary?
1010010010001001 (hexadecimal A489, octal 122211).
What is the square root of 42121?
About 205.2340.
Is 42121 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 42121?
42121 is a semiprime: 73 × 577, the product of two primes.