Adding to 396 its sum of digits (18), we get a palindrome (414).
Subtracting from 396 its sum of digits (18), we obtain a triangular number (378 = T27).
396 divided by its sum of digits (18) gives a palindrome (22).
Adding to 396 its reverse (693), we get a square (1089 = 332).
396 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.
It is a tau number, because it is divible by the number of its divisors (18).
It is a nude number because it is divisible by every one of its digits.
It is a plaindrome in base 13 and base 16.
It is a nialpdrome in base 11.
It is a zygodrome in base 2 and base 3.
396 is a gapful number since it is divisible by the number (36) formed by its first and last digit.
396 is the 11-th nonagonal number.
It is an amenable number.
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
396 is a wasteful number, since it uses less digits than its factorization.
396 is an evil number, because the sum of its binary digits is even.
The square root of 396 is about 19.8997487421. The cubic root of 396 is about 7.3434204620.