[Users] vzctl --cpuunits max?

[Rene C.]

I have a server with 12 cores and vzcpucheck reports following "power
of the node":
[root at server16 ~]# vzcpucheck
Current CPU utilization: 646833
Power of the node: 2085210

Essentially I want to allow one container 2/3 of the power of this
hardware node but if I set the value of --cpuunits to more than 500000
it throws the error

[root at server16 ~]# vzctl set 1602 --save --cpus 8 --cpulimit 800
--cpuunits 500001
Bad parameter for --cpuunits: 500001

Setting it to 500000 works fine:

[root at server16 ~]# vzctl set 1602 --save --cpus 8 --cpulimit 800
--cpuunits 500000
Setting CPU limit: 800
Setting CPU units: 500000
Setting CPUs: 8
CT configuration saved to /etc/vz/conf/1602.conf

What am I misunderstanding here?