SOYBEAN VARIETY SM16617721

A novel soybean variety, designated SM16617721 is provided. Also provided are the seeds of soybean variety SM16617721, cells from soybean variety SM16617721, plants of soybean SM16617721, and plant parts of soybean variety SM16617721. Methods provided include producing a soybean plant by crossing soybean variety SM16617721 with another soybean plant, methods for introgressing a transgenic trait, a mutant trait, and/or a native trait into soybean variety SM16617721, methods for producing other soybean varieties or plant parts derived from soybean variety SM16617721, and methods of characterizing soybean variety SM16617721. Soybean seed, cells, plants, germplasm, breeding lines, varieties, and plant parts produced by these methods and/or derived from soybean variety SM16617721 are further provided.