==Anecdotes==
*'''Motto:''' What's your number? Hello, we are SECRET NUMBER! *They explained that their name stands for the special numbers every person has in their passwords and PIN codes, such as their birthdays or some other special number, and they wanted to have this kind of special meaning for the public.<span class="reference" id="cite_ref-showcase_6-0"></span> They also explained that the five stars in the box of their logo represents the five members.*Three of the members were already known in show business, Léa was a member of MIXNINE and also a former member of SKARF. Jinny and Denise were popular YG Entertainment trainees. Denise was first known as one of the participants in Kpop Star 5 singer competition before joining YG Entertainment and Jinny later participated in PRODUCE 48 as an <span class="reference" id="cite_ref-showcase_6-0"></span>independent trainee.*Their role model is the girl group Apink.
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