It is a Jordan-Polya number, since it can be written as (3!)5.
It is a tau number, because it is divible by the number of its divisors (36).
It is an Ulam number.
It is a nialpdrome in base 6 and base 10.
It is a zygodrome in base 2.
It is a congruent number.
It is an unprimeable number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 7776, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (11466).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
7776 is an equidigital number, since it uses as much as digits as its factorization.
7776 is an evil number, because the sum of its binary digits is even.
The square root of 7776 is about 88.1816307402. The cubic root of 7776 is about 19.8115634934.
Multiplying 7776 by its product of digits (2058), we get a cube (16003008 = 2523).
Subtracting from 7776 its reverse (6777), we obtain a palindrome (999).
The spelling of 7776 in words is "seven thousand, seven hundred seventy-six".