Find installation date and time of rpm package(s)

List all rpm package with date and time information, use the below given command to list all rpm package with date-stamp information:

rpm -qa --last

iotop-0.4.3-7.8.1 Fri Aug 7 12:24:02 2015
libgtop-lang-2.28.0-1.9.24 Fri Aug 7 12:20:57 2015
libgtop-2.28.0-1.9.24 Fri Aug 7 12:20:10 2015
libgtop-2_0-7-2.28.0-1.9.24 Fri Aug 7 12:20:06 2015

and for a single package:

rpm -q --last package-name

Useful RPM Commands

Getting detailed information about the package telnet:
root# rpm -qi telnet
Name : telnet
Epoch : 1
Version : 0.17
Release : 59.el7
Architecture: x86_64
Install Date: Thu 16 Jul 2015 13:49:27 IST
Group : Applications/Internet
Size : 115772
License : BSD
Signature : RSA/SHA256, Fri 04 Jul 2014 06:12:17 IST, Key ID 24c6a8a7f4a80eb5
Source RPM : telnet-0.17-59.el7.src.rpm
Build Date : Mon 09 Jun 2014 23:06:27 IST
Build Host :
Relocations : (not relocatable)
Packager : CentOS BuildSystem
Vendor : CentOS
Summary : The client program for the Telnet remote login protocol
Description :
Telnet is a popular protocol for logging into remote systems over the
Internet. The package provides a command line Telnet client

Determining which package installed the file /usr/bin/telnet:
root# rpm -qf /usr/bin/telnet

Showing all the files installed by the package telnet:
root# rpm -ql telnet

Viewing the documentation files for the command telnet:
root# rpm -qd telnet