One of my YC batchmates had his company acquired by Google. They quickly shut down his product (shocking!) and had him product manage Google Fi instead. He gave me access to the beta about 7 years ago. At that time, you could search for any string of numbers and it would let you see available numbers containing that string. I was able to get a number with 4 consecutive zeros in it and to this day it brings me joy every time I see or share it. Most people are not as amused but every now and then I'll meet someone who lights up when they see it. Without fail, they were also a math nerd growing up. I guess numbers tickle some people's brains differently.