64198-64296 Assigned by ARIN whois.arin.net https://rdap.arin.net/registryhttp://rdap.arin.net/registry 2015-04-29
64297-64395 Assigned by APNIC whois.apnic.net https://rdap.apnic.net/ 2016-05-25
64396-64495 Assigned by RIPE NCC whois.ripe.net https://rdap.db.ripe.net/ 2016-07-29
64496-64511 Reserved for use in documentation and sample code [RFC5398] 2008-12-03
64512-65534 Reserved for Private Use [RFC6996]
65535 Reserved [RFC7300]
This here is the up to date list of the assigned ASN https://www.iana.org/assignments/as-numbers/as-numbers.xhtml Currently 64198-64495 would be blocked, but those ASN are already in use.
64198-64296 Assigned by ARIN whois.arin.net https://rdap.arin.net/registry http://rdap.arin.net/registry 2015-04-29 64297-64395 Assigned by APNIC whois.apnic.net https://rdap.apnic.net/ 2016-05-25 64396-64495 Assigned by RIPE NCC whois.ripe.net https://rdap.db.ripe.net/ 2016-07-29 64496-64511 Reserved for use in documentation and sample code [RFC5398] 2008-12-03 64512-65534 Reserved for Private Use [RFC6996]
65535 Reserved [RFC7300]