The IMSI is used in mobile radio to uniquely identify the network subscriber. The first 5 digits are the MCC and the MNC, which are required in the configuration of some devices.
Your Tele2 M2M SIM cards are so-called single IMSI cards. This means that a single IMSI is stored on the SIM card. The Mobile Country Code (MCC) is 240 by default, the Mobile Network Code (MNC) is 07. The complete IMSI can be viewed in the portal in the device view.