Dahdi show channels

I have a Digium te133 T1 card running on a freepbx 2.11.0 system.

The dadi show channels command outputs:

localhost*CLI> dahdi show channels
Chan Extension Context Language MOH Interpret Blocked State Description
pseudo default default In Service
1 from-digital en default In Service
2 from-digital en default In Service
3 from-digital en default In Service
4 from-digital en default In Service
5 from-digital en default In Service
6 from-digital en default In Service
7 from-digital en default In Service
8 from-digital en default In Service
9 1707616760 from-digital en default In Service
10 from-digital en default In Service
11 from-digital en default In Service
12 from-digital en default In Service
13 1800967304 from-digital en default In Service
14 1505349826 from-digital en default In Service
15 1505349463 from-digital en default In Service
16 1800967304 from-digital en default In Service
17 6217881 from-digital en default In Service
18 5244646 from-digital en default In Service
19 6497384 from-digital en default In Service
20 6497389 from-digital en default In Service
21 1800967304 from-digital en default In Service
22 1800967304 from-digital en default In Service
23 6497384 from-digital en default In Service

My question is that I ran the command when there were no active calls. Why does the extension column have numbers in it? Is the system not properly hanging up the channels?

From Asterisk CLI:-

core show channels verbose