For most people, numbers have a negative connotation. We associate numbers with math, taxes, or bills. All things, for the most part, people do not enjoy dealing with.
Research done by Radiolab, it was found that numbers can have more connotations than just those generalities. Radiolab a nationally syndicated radio program produced by WNYC, a public radio station in New York City, and broadcast on public radio stations in the United States. They found that people have the tendency to anthropomorphize, or attribute human personality to certain numbers. For example, people tend to associate the number 1 with "independent" and "strong", where as the number 2 is generally associated with "sympathetic" and "nurturing".
This knowledge can come especially in handy for company's branding efforts. Companies who use numbers in their names and logos can have a specific advantage over competitors when used tactfully. Levi's 501 jeans do this perfectly. The line is meant to be innovative, new, and unexpected. With the number 501, the brand goes just beyond what is expected.
Oxy-10 acne cream does the same. With the usage of the number 10, customers associate it with no-nonsense. In this number, "we get to a solution. Ten is where our hands run out, so there is a sense of completion there. We’ve gone through the process and we’re going to come out OK." This is perfect for a brand with a product such as acne cream where an definite solution is wanted.