Fixed line
Numbers starting with 6537
1 Singapore fixed line number in this prefix appear on public websites.
About the 6537 prefix
This looks like a Singapore fixed-line number. Reports often mention company switchboards, delivery callbacks, property agents, or unsolicited sales calls.
6-prefix numbers are commonly used for Singapore fixed-line services. Numbers in this list are written locally as 6537 xxxx, internationally as +65 6537 xxxx, and as 8-digit 6537xxxx.