在特定日期运行命令而不使用“ at”命令

I want to set an execution date for a command and it seems that vmware ESXI operating system has no at command. So, I am thinking about writing

#!/bin/bash
N=$1
sleep N
./run_program

Assuming that I want to execute run_program after 20 days, I will run ./script 1728000 &. Not a bad thing, but is there any better idea about that?