This question is frequently asked, and frequently answered, in the forum. In fact, there are two separate community FAQs about it.
In order to figure out what is best at your own home, you have to look at two different things.
What Wi-Fi channel is your Wi-Fi router using? This will normally be 1, 6, or 11.
What Zigbee channel is your smartthings/aeotec hub using? This will be listed in the IDE.
The frequencies for these two sets of channels overlap each other, but the channel numbers are not identical. For example, Wi-Fi channel 11 is very far away from Zigbee channel 11, and that’s a good thing. you want them to be as far apart as possible so they don’t interfere with each other. (specifically so that Wi-Fi doesn’t drown out Zigbee, Wi-Fi is a much stronger signal.)
Please see the existing community FAQ:
FAQ: What WiFi Channel is least likely to interfere with SmartThings?