Can stolen iPhone be blocked with IMEI number?

can I block it with the imei number

You can't, but your carrier might be willing to "blacklist" the phone if you contact them. There are both upsides and downsides to this.

For example if you decide that you want to protect your data by erasing the phone remotely using Find My, you won't be able to do this since the erase instructions will never reach the phone.

Please follow these instructions:

Find your lost iPhone or iPad with Find My - Apple Support