Yes, 7523.pl can receive emails.
Yes, 7523.pl seems to be a legitimate domain.
A record
195.42.113.24
MX records
ALT1.ASPMX.L.GOOGLE.COM.
64.233.186.27
ALT2.ASPMX.L.GOOGLE.COM.
209.85.202.27
ASPMX.L.GOOGLE.COM.
172.217.222.27
ASPMX2.GOOGLEMAIL.COM.
64.233.186.27
ASPMX3.GOOGLEMAIL.COM.
209.85.202.26