The number 42409
42409 is a twin prime (42407 and 42409 are both prime) and the 4435th prime number. Its only divisors are 1 and 42409.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42409: a twin prime (42407 and 42409 are both prime); the 4435th prime number.
- 2
42409 is prime, so its only factors are 1 and 42409. It is the 4435th prime; the next prime is 42433 and the one before is 42407.
- 3
The divisors add up to 42410; without 42409 itself that is 1, so 42409 is deficient (1 is less than 42409). Euler's totient φ(42409) = 42408 numbers up to 42409 share no factor with it.
- 4
The digits of 42409 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 132 steps to reach 1.
42409 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 42410 |
| Euler totient φ(n) | 42408 |
| Square | 1798523281 |
| Cube | 76273573823929 |
| Square root | 205.934456 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 132 |
| Scientific notation | 4.2409 × |
42409 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand four hundred and nine |
| Binary (base 2) | 1010010110101001 |
| Octal (base 8) | 122651 |
| Hexadecimal (base 16) | A5A9 |
| Base 3 | 2011011201 |
| As time | 42409 seconds = 11 h 46 min 49 s |
Is 42409 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 4) | 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 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 9) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42409 a prime number?
Yes. 42409 is divisible only by 1 and itself.
What are the factors of 42409?
1, 42409.
What is 42409 in binary?
1010010110101001 (hexadecimal A5A9, octal 122651).
What is the square root of 42409?
About 205.9345.
Is 42409 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 42409?
42409 is a twin prime (42407 and 42409 are both prime); the 4435th prime number.