Thank you for sharing your beautiful cactus bloom. I find such blooms extra appealing. Who would think something so large and beautiful could be produced by a thorny little cactus. Awesome.
I'm surprised it isn't fragrant. It is a member of the night blooming Cereus (Peniocereus)( queen of the night cactus - Google Search). they come in all shapes and colors but usually white and usually very fragrant. They open at night and by dawn, they begin to fade and are usually wilted by day's end. I have two that will be flowering in a few weeks and I will try to post.