Submitted information about SNPs (assay records) are assigned a "ss..." identifiers. Submissions that fall on the same genomic location are accumulated in SNP clusters that are assigned "rs..." identifiers.
Are there 53,558,214 locations for SNPs in human beings? Well, probably not. The number you gave also concerns clusters that have not been validated (What exactly does it mean when a SNP is validated), where the number of non-computationally verified or SNPs with frequency information is already lower: 38,077,993 (from the same web-page link you gave). However, since dbSNP SNP clusters can also loose their validation status, this number might go up or down in the future -- depending on the scrutiny of researchers as further data becomes available.