The number 42157
42157 is the 4406th prime number. Its only divisors are 1 and 42157.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42157: the 4406th prime number.
- 2
42157 is prime, so its only factors are 1 and 42157. It is the 4406th prime; the next prime is 42169 and the one before is 42139.
- 3
The divisors add up to 42158; without 42157 itself that is 1, so 42157 is deficient (1 is less than 42157). Euler's totient φ(42157) = 42156 numbers up to 42157 share no factor with it.
- 4
The digits of 42157 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 194 steps to reach 1.
42157 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 42158 |
| Euler totient φ(n) | 42156 |
| Square | 1777212649 |
| Cube | 74921953643893 |
| Square root | 205.321699 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 194 |
| Scientific notation | 4.2157 × |
42157 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand one hundred and fifty-seven |
| Binary (base 2) | 1010010010101101 |
| Octal (base 8) | 122255 |
| Hexadecimal (base 16) | A4AD |
| Base 3 | 2010211101 |
| As time | 42157 seconds = 11 h 42 min 37 s |
Is 42157 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 2) | 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 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 5) | 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 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | 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 42157 a prime number?
Yes. 42157 is divisible only by 1 and itself.
What are the factors of 42157?
1, 42157.
What is 42157 in binary?
1010010010101101 (hexadecimal A4AD, octal 122255).
What is the square root of 42157?
About 205.3217.
Is 42157 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 42157?
42157 is the 4406th prime number.