But what's a humble number? (3)

By definition, a humble number is a number whose prime factors consists of 2, 3, 5, or 7. It is a number of the form $2^{a} \times 3^{b} \times 5^{c} \times 7^{d}$ , where $a, b, c$ , and $d$ are non-negative integers.

Since $210$ is a humble number, it can divide any humble number of the form $2^{a} \times 3^{b} \times 5^{c} \times 7^{d}$ , where $a, b, c,$ and $d$ are integers all greater than or equal to 1.