• 864 can be written using four 4's:
It is a Jordan-Polya number, since it can be written as 4! ⋅ (3!)2.
864 is an esthetic number in base 7, because in such base its adjacent digits differ by 1.
It is a tau number, because it is divible by the number of its divisors (24).
It is a nude number because it is divisible by every one of its digits.
It is an Ulam number.
It is a straight-line number, since its digits are in arithmetic progression.
It is a plaindrome in base 14.
It is a nialpdrome in base 6, base 10 and base 12.
It is a congruent number.
2864 is an apocalyptic number.
It is an amenable number.
It is a practical number, because each smaller number is the sum of distinct divisors of 864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1260).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
864 is a wasteful number, since it uses less digits than its factorization.
864 is an evil number, because the sum of its binary digits is even.
The square root of 864 is about 29.3938769134. The cubic root of 864 is about 9.5244063118.
The spelling of 864 in words is "eight hundred sixty-four", and thus it is an aban number.