Online Calculate Sum of Proper Divisors

<div id="vueapp">
  positive integer: <input v-model="intn" placeholder="Input positive integer">
  <p>Prime Factors: {{ primes }}</p>
  <p>Sum of Proper Divisors: {{ sum }}</p>
</div>

<script src="https://cdn.jsdelivr.net/npm/vue@2.5.16/dist/vue.js"></script>

'use strict';

// Get all prime factors of a given number n
function PrimeFactors(n) {
  if (n==1) {return [1];}

  var pfs = [];
  // Get the number of 2s that divide n
  while (n%2 == 0) {
    pfs.push(2);
    n /= 2;
  }

  // n must be odd at this point. so we can skip one element
  // (note i = i + 2)
  for (var i=3; i*i <= n; i += 2) {
    // while i divides n, append i and divide n
    while (n%i == 0) {
      pfs.push(i);
      n /= i;
    }
  }

  // This condition is to handle the case when n is a prime number
  // greater than 2
  if ( n>2 ) {
    pfs.push(n);
  }

  return pfs;
}

function SumOfDivisors(pfs) {
  var m = {};
  for (var i = 0; i < pfs.length; i++) {
    var prime = pfs[i];
    if (m.hasOwnProperty(prime)) {
      m[prime] += 1;
    } else {
      m[prime] = 1;
    }
  }

  var sum = 1;
  for (var prime in m) {
    var exponents = m[prime];
    sum *= (Math.pow(prime, exponents+1)-1) / (prime-1);
  }
  return sum;
}

new Vue({
  el: '#vueapp',
  data: {
    intn: 284,
    primes: "",
    sum: ""
  },
  watch: {
    intn: {
      immediate: true,
      handler(val, oldVal) {
        var n = parseInt(val);
        if (isNaN(n) || n<1) {
          this.primes = "please input positive integer";
          return;
        }

        var pfs = PrimeFactors(n);
        this.primes = pfs;
        this.sum = (SumOfDivisors(pfs) - n);
      }
    }
  }
});