sharepoint - Strange 'lastModifiedDateTime' object when requesting a sharepoint site with microsoft graph api

Question

I am trying to detect sharepoint sites in Office 365 not visited last 180 days. With this purpose I query sharepoint sites using a microsoft graph api query like this: GET https://graph.microsoft.com/v1.0/sites?search= which returns an JSON object where object['value'] is the first portion of site objects and object['@odata.nextLink'] is the link to the next portion of site objects (as I understand from what I see in the output) When I view site objects which look like this:

 'id': 'mytenant.sharepoint.com,29c17bd8-db42-430d-b5ba-b55d15885790,6302ea22-aa16-4e12-bd50-6e7094fc65cd',
 'lastModifiedDateTime': '0001-01-01T08:00:00Z',
 'name': 'TEST_MODIFIED_DATE',
 'webUrl': 'https://mytenant.sharepoint.com/sites/TEST_MODIFIED_DATE',
 'displayName': 'TEST_MODIFIED_DATE',
 'root': {},
 'siteCollection': {'hostname': 'mytenant.sharepoint.com'}}

in a loop I can see 'lastModifiedDateTime' property which may (or may not) be what I am looking for. Some sites and this one in particular have a strange value of 'lastModifiedDateTime': 'lastModifiedDateTime': '0001-01-01T08:00:00Z'

1. What does this strange datetime value mean?
2. Does it mean the last time the site was visited at all? It does not correspond with the value I can see in Sharepoint web interface ('last activity' column, which is now empty for this site)?

Answer 1

You can try using the 'id' that you have got from the search query and try to use that site id in the following query. https://graph.microsoft.com/v1.0/sites{siteid} You can get the right lastModifiedDateTime as shown below.

Please go through this document.