Question

How to check whether a given number is a twisted prime number in JavaScript

Answer 1

// A number is a twisted prime number if the reverse of the number is also a prime number
  
function reverseNumber(n) {
    let reverse = 0;
    let reminder;
  
    while (n != 0) {
        reminder = n % 10;
        reverse = reverse * 10 + reminder;
        n = Math.trunc(n / 10);  
    }
    return reverse;
}
  
function isPrime(n) {
    if (n < 2 || (n % 2 == 0 && n != 2)) {
        return 0;
    }
  
    const count = Math.floor(Math.sqrt(n));
    for (let i = 3; i <= count; i += 2) {
        if (n % i == 0) {
            return 0;
        }
    }
    return 1;
}
  
const n = 79;
const reverse_n = reverseNumber(n);
  
if (isPrime(n) && isPrime(reverse_n)) {
    console.log("Twisted prime number");
} else {
    console.log("Not twisted prime number");
}
  
  
  
  
/*
run:
  
"Twisted prime number"
  
*/

 

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