The number 42100
42100 is a composite number with 18 divisors. Its prime factorisation is × × 421. Divisors (18): 1, 2, 4, 5, 10, 20, 25, 50, 100, 421, 842, 1684, 2105, 4210, 8420, 10525 … 42100.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42100 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42100 is composite. Its prime factorisation is
- 3
The divisors add up to 91574; without 42100 itself that is 49474, so 42100 is abundant (49474 is more than 42100). Euler's totient φ(42100) = 16800 numbers up to 42100 share no factor with it.
- 4
The digits of 42100 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 194 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42100 = 2^{2} \times 5^{2} \times 421 \]42100 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 18 |
| Sum of divisors | 91574 |
| Euler totient φ(n) | 16800 |
| Square | 1772410000 |
| Cube | 74618461000000 |
| Square root | 205.182845 (= 10√421) |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 194 |
| Scientific notation | 4.21 × |
42100 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand one hundred |
| Binary (base 2) | 1010010001110100 |
| Octal (base 8) | 122164 |
| Hexadecimal (base 16) | A474 |
| Base 3 | 2010202021 |
| As time | 42100 seconds = 11 h 41 min 40 s |
Is 42100 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42100 ÷ 2 = 21050) | 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 | Yes (42100 ÷ 4 = 10525) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (42100 ÷ 5 = 8420) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 4) | 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 | Yes (42100 ÷ 10 = 4210) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42100 a prime number?
No. 42100 = × × 421, so it is divisible by 2.
What are the factors of 42100?
1, 2, 4, 5, 10, 20, 25, 50, 100, 421, 842, 1684, 2105, 4210, 8420, 10525, 21050, 42100.
What is 42100 in binary?
1010010001110100 (hexadecimal A474, octal 122164).
What is the square root of 42100?
About 205.1828, exactly 10√421.
Is 42100 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 42100?
It is a composite number with 18 divisors.