27728 is a product of a power of 2 and a 4k+1 prime and so it can be expressed as a sum of two squares in one way only viz. 152^2 + 68^2.

27728 is a member of OEIS A331824: starts of runs of 4 consecutive positive negabinary-Niven numbers.

27728 is a junction number because it is equal to n+sod(n) for n = 27697 and 27706.

27728 is an untouchable number.

27728 can be rendered as a digit equation as follows:

2 ^ (7 / 7 + 2) = 8