Tbqh nobody says this about numbers. This is just a meme for popsci and Hollywood biopics.
Mathematician are often motivate by beauty, but it's not numbers themselves, or equations themselves that are beautiful. It's the relationships, symmetries, patterns, isomorphisms, generalizations, dualities, and correspondences between intuitively distinct systems that mathematicians find beautiful. It's the beautiful regularities and deep similarities between theories that they find beautiful. It's also the surprising structures, anomalies, counterexamples, and weird odds and ends (e.g. Non standard models of arithmetic, the monitor group, the incompleteness theorems, non-differentiable but everywhere continuous functions, etc.) It's also the wide range of applicability of fields like differential equations and combinatorics, and the omnipresence of patterns and cycles in nature, as well as the spontaneous formation of order within dynamical systems and other large and complex objects in nature.