4001.org
Read a numeric domain aloud to someone in Mandarin, Arabic, Spanish or English and it lands identically every time. That property is why numerics have held a durable international following while the keyword market went through its cycles.
4001 has a shape as well as a value. It’s the number just past a round four thousand, which reads as a model number, a room, a specification, a channel or a standard. Plenty of organisations use numeric identifiers as part of their identity, more than people expect, and a clean four-digit address serves them permanently.
Four digits is also phone-number territory, a chunk size people are already practised at remembering.
No letters, no hyphen, nothing to spell, and the easiest kind of domain there is to read out over a bad connection.
Enquiries welcome.