Are there any positives/negatives in this rejection email ? or, it is just a desk rejection? I received the following rejection email today :

Dear Prof. XXX,
This message concerns the manuscript
XXXX by XXX
submitted to XXXXX journal.
Informal consultations with possible reviewers have persuaded me that
your article is too specialized for our journal, and therefore I am
sorry to say we cannot accept it for publication.  We have elected not
to review it fully so as not to cause undue delays in its eventual
publication.
I advise you to submit it to a journal more narrowly focused on number
theory, and I do wish you success in publishing it elsewhere.

Now, my question is:
Are there any positives/negatives that can be taken from this email ? or, it is just a desk rejection ?
Note that I received this email 20 days after the submission.
This is a desk rejection. There's not much more to say about it - I suppose you could say that they haven't outright said your paper is incorrect, which is a positive; on the other hand they did also say that they are not considering your paper and you should submit elsewhere, which is effectively the same as rejection and certainly a negative thing.
There's nothing to do but submit elsewhere.