Especially in the last couple of centuries, but probably as long as maths existed, people have talked about the so-called idea of 'mathematical philosophy'. It exists, and besides philosophers, who often have practical ideas, it is also an idea scientists talk about who really know almost nothing about pure mathematics and what 'mathematical philosophy' deals with in the minds of mathematicians, but because of this and for other reasons, a better term is 'philosophical mathematics.'
Purely mathematical philosophy--in other words, philosophical math, or maths applied to the questions of philosophy--can be called 'mathematicism', which is (according to OED) 'the opinion that everything can be described ultimately in mathematical terms, or that the universe is fundamentally mathematical'. Philosophical maths is only rationalist/gnostic idealist maths (idealism/mentalist/spiritualist is the philosophy only something that has to do with an abstract idea except for matter, such as mind/spirit, exists) and not weak empiricist materialism (empiricism is the idea that only the senses show truth, such as our ancestors using their senses as the basis to conclude that the sun was magic or a divinity, and empiricism is the school of thought opposing rationalism so can also be called 'irrationalism') that avoids the issues. Philosophical maths is possible, and is the only real math, and is actually superior to philosophy without math, as evidenced in the teachings of Pythagoras, Socrates & Plato, in which maths was considered the best subject to train philosophers. In Hegelian terms, philosophy is a thesis, science is its antithesis, and maths is their synthesis. Philosophy often takes a rationalist idealist viewpoint and sometimes deals with the subjective, but science often takes the opposing empiricist materialist viewpoint and claims to deal with the objective. Maths is traditionally rationalist empiricist and focused on the objective, though it can be applied to the subjective.
Maths is generally considered the most difficult subject. It is the supreme subject. Maths is the subject that has been built up over millennia until it has actually become the vastest area of knowledge. Even science fully depends on maths, but maths does not depend on anything.
Even some scientists think that reality is entirely mathematical, which is of course the viewpoint of philosophical maths. Pythagoras said 'all is number', 'number rules the universe', which Plato paraphrased. Everything is math; maths explains everything and is the only ideal (Platonic), perfect, absolute, immutable, eternal truth. Maths is the grand unified theory of everything. Maths explains reality and is why reality is the way it is; maths is why reality and everything even exists; mathematical objects and their processes are the causes of the universe. If anything really must be called 'the Divine,' or a 'creator,' it is maths (as processes of mathematical 'life'/mind/spirit/monad... same thing.)
Maths is not just the Divine, it is the only way to enlightenment, liberation, perfection, apotheosis.
Mathematicians should study philosophical/pure math, which true mathematicians understand and apply to life.
The term 'philosophical mathematics' (called a 'hyperrationalist idealism' for focusing on math as well as logic,) originated in articles/books, such as The God Game (with views on atheism, panendeism, ‘mathematics-theism’) ( (also available on Lulu.com, Smashwords.com, and from commercial ebook stores.) by modern (Neo)Pythagorean-(Neo)Platonist-Leibnizians (who use ideas from many great philosopher-mathematicians such as René Descartes, Gottfried Leibniz, Kurt Gödel). Some of their writings are controversial, but some also have new ideas in philosophy, science, and math. Later they redefined 'philosophical mathematics' 'ontological mathematics,' though it has also been used to describe cosmology (ontology and cosmology being branches of metaphysics, a branch of philosophy.)