May I recommend the Unix utility split (1)?

NAME
     split -- split a file into pieces

SYNOPSIS
     split [-a suffix_length] [-b byte_count[k|m] | -l line_count -n
           chunk_count] [file [name]]

DESCRIPTION
     The split utility reads the given file and breaks it up into files of
     1000 lines each.  If file is a single dash or absent, split reads from
     the standard input.  file itself is not altered.

     The options are as follows:

[...]

     -n      Split file into chunk_count smaller files.

Okay, maybe that was a bad suggestion. The GNU version does not have a split-to-n-chunks feature, it seems.