The number of Lookup relationship that an object can have are as in today ?
Master-Detail Relationship Fields, per Object (Standard or Custom) --> 2
Total Relationship Fields (Master-Detail + Lookup), per Object (Standard or Custom) --> 40
38 Lookup and 2 MD
39 Lookup and 1 MD relationship fields on an object
Please check this link:
By default, the system is limited to 40 lookup fields per object, up to two of which may be master-detail relationships if it is a custom object. You can request more than the 40 relationship per object limit if absolutely necessary, although there are performance implications for doing so. The absolute limit that you can request is 50.
**Considerations for Relationships**
Each custom object can have up to two master-detail relationships and many lookup relationships. Each relationship is included in the maximum number of custom fields allowed.
- The Total relationship field included lookup can be 40 by default. As @sfdcFox said, it can be increased if needed by raising a request to salesforce up to 50.
Earlier it was 25, after Summer ’14 Release, The default number of Relationship Fields per object has been increased, from 25 fields to 40 fields.