You can check which operator the mobile phone number belongs to in the following ways:

1. Query through the operator’s official website: Different operators’ official websites may have different query entrances. Generally, You can find the entrances such as "Number Attribution Query", "Number Information Query" or "Number Query" on the homepage or customer service center page, and then you need to follow the page prompts to enter the mobile phone number and verification code to query the belonging operator information.

2. Query through third-party query platforms: Some third-party query platforms provide query services for mobile phone ownership operators, such as "Baidu Mobile Phone Ownership Query", "Taobao Mobile Phone Ownership Query", etc., you can Enter your mobile phone number to check.

3. Inquiry through the operator's official customer service hotline: Call the operator's customer service hotline and provide the customer service staff with your mobile phone number and personal information for inquiry.

I hope the above information can help you.