The numerator and denominator are mutually prime (no common factors), and thus the fraction is fully reduced. How else would you represent it as a fraction?

#!/usr/bin/env perl -l
use warnings;
use strict;

#####
# [id://56906] for quick gcf
sub gcf {
  my ($x, $y) = @_;
  ($x, $y) = ($y, $x % $y) while $y;
  return $x;
}

######

print gcf(49420098210293,100000000000000);  # prints 1

#####

use Math::Prime::Util qw/is_prime factor/;
print is_prime(49420098210293);             # not prime (I wasn't sure
+ when I started my answer)
local $, = 'x';
print factor(49420098210293);               # 113x4729x92481709
print factor(100000000000000);              # 2x2x2x2x2x2x2x2x2x2x2x2x
+2x2x5x5x5x5x5x5x5x5x5x5x5x5x5x5
# no common factors
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