use warnings;
use strict;
use Math::BigFloat;
use feature ':5.10';

my $x = Math::BigFloat->new('954846259588805228035541587771');

print $x->bdstr(), "\n";
print $x, "\n";
say $x;

printf "%.0f\n", $x;
printf "%.29e\n", 954846259588805228035541587771;

__END__

Outputs:

954846259588805228035541587771
954846259588805228035541587771
954846259588805228035541587771
954846259588805282215996948480
9.54846259588805282215996948480e+29