Android—IMEI

         TelephonyManager telephonyManager= (TelephonyManager) getSystemService(TELEPHONY_SERVICE);
 //        Returns the unique device ID, for example, the IMEI for GSM and the MEID
 //        or ESN for CDMA phones. Return null if device ID is not available.
         String deviceId=telephonyManager.getDeviceId();

<uses-permission android:name="android.permission.READ_PHONE_STATE"/>