To find out whose phone number it is, you can use free reverse phone lookup services that identify the owner of a phone number by searching databases. Some of the best options include:

• Truecaller: Enter the phone number to find out who called you within seconds

• NumLookup: Provides the owner's full name, location, carrier, and social media profiles for US numbers with no registration required

• Whitepages: Offers detailed information such as name, address, carrier, and spam reports. It also verifies if the number is active

• Sync.ME: Identifies unknown callers and blocks spam calls, showing caller details even if not in your contacts

These services work by entering the phone number in their search tool, and they return information about the owner if available. For UK numbers, "Who Called Me" is a dedicated free reverse lookup service

. If you provide the specific phone number, I can guide you on which service to use or how to proceed. Otherwise, you can try one of the above tools to identify the owner of the phone number.