172 (one hundred [and] seventy-two) is the natural number following 171 and preceding 173.
172 is a part of a near-miss for being a counterexample to Fermat's Last Theorem, as 135<sup>3</sup> + 138<sup>3</sup> = 172<sup>3</sup> − 1. This is only the third near-miss of this form, two cubes adding to one less than a third cube. It is also a "thickened cube number", half an odd cube (7<sup>3</sup> = 343) rounded up to the next integer.