What amazing and huge flowers! It certainly looks like the flowers of Echinopsis, I see online, but I don't know the cactus very well. Looks like the genus has variable form. I actually have Echinopsis huascha on my desk and it did bloom shortly after it was first given to me, but not since. Maybe it needs to spend some time outside in cooler temps.
Many cactus species has variable spine length, and this is one of them. Individual plants with unusually short spines may look spineless even if they technically do have spines.
