864666 has 36 divisors (see below), whose sum is σ = 2064426. Its totient is φ = 261360.

The previous prime is 864641. The next prime is 864673. The reversal of 864666 is 666468.

864666 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 680625 + 184041 = 825^2 + 429^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 864666.

It is an unprimeable number.

864666 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1980 + ... + 2376.

2⁸⁶⁴⁶⁶⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 864666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1032213).

864666 is an abundant number, since it is smaller than the sum of its proper divisors (1199760).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

864666 is a wasteful number, since it uses less digits than its factorization.

864666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 427 (or 413 counting only the distinct ones).

The product of its digits is 41472, while the sum is 36.

The square root of 864666 is about 929.8741850380. The cubic root of 864666 is about 95.2685292656.

The spelling of 864666 in words is "eight hundred sixty-four thousand, six hundred sixty-six".