It is a square number, being 52 = 5 × 5, and hence the third non-unitary square prime of the form p2.
It is one of two two-digit numbers whose square and higher powers of the number also ends in the same last two digits, e.g., 252 = 625; the other is 76.
25 has an even aliquot sum of 6, which is itself the first even and perfect number root of an aliquot sequence; not ending in (1 and 0).
It is the smallest square that is also a sum of two (non-zero) squares: 25 = 32 + 42. Hence, it often appears in illustrations of the Pythagorean theorem.
25 is the sum of the five consecutive single-digit odd natural numbers 1, 3, 5, 7, and 9.
in a 24-cell honeycomb, twenty-four 24-cells surround a single 24-cell, and where
a faceting of the 600-cell with symmetry can otherwise also be constructed, with cells overlapping.[9]
The 24-cell can be further generated using three copies of the 8-cell, where the 24-cell honeycomb is dual to the 16-cell honeycomb (with the tesseract the dual polytope to the 16-cell).
that features the only non-trivial solution, i.e. aside from , to the cannonball problem where sum of the squares of the first twenty-five natural numbers in is in equivalence with the square of [11] (that is the fiftieth composite).[12] The Leech lattice, meanwhile, is constructed in multiple ways, one of which is through copies of the lattice in eight dimensions[13]isomorphic to the 600-cell,[14] where twenty-five 24-cells fit; a set of these twenty-five integers can also generate the twenty-fourth triangular number, whose value twice over is [15]
In religion
In Ezekiel's vision of a new temple: The number twenty-five is of cardinal importance in Ezekiel's Temple Vision (in the Bible, Ezekiel chapters 40–48).[16]