$ cat 892828_a.pl
#!/usr/bin/perl
use strict;
use warnings;

my ($M, $N) = (9999997, 3);

my @ranges = map { $_ * int($M/$N) } 0 .. $N-1;
@ranges    = map { [ $ranges[$_], $ranges[$_+1]//$M ] } 0 .. $N-1;

print join(", ", map { "(".join("-",@{$_}).")" } @ranges), "\n";

$ perl 892828_a.pl
(0-3333332), (3333332-6666664), (6666664-9999997)