numbers have all of mathematics as a background which is what makes it so easy to design apis for them
graphs are a much newer development, I think there's a very deep connection between category theory and graphs in general (and also computers make both much more useful somehow)
lambda calculus can be used to define numbers but it's a wonky construction, it's reminiscent of how sets can also be used to define numbers.
the python runtime includes four built-in number types (small integer, arbitrary-precision integer, float, and complex) and the python standard library includes two more number types (decimal and fractions), and one of the most popular non-standard libraries for python is numpy, which provides some other kinds of numbers such as single-precision floats, vectors, and matrices. other systems like pari/gp have number libraries that provide other kinds of numbers, such as p-adic numbers and galois field elements
the only programming languages i've ever used that didn't have 'number' libraries were esoteric languages like brainfuck and the lambda calculus