866609028 has 18 divisors (see below), whose sum is σ = 2190595134. Its totient is φ = 288869664.

The previous prime is 866608991. The next prime is 866609033. The reversal of 866609028 is 820906668.

It can be written as a sum of positive squares in only one way, i.e., 818417664 + 48191364 = 28608^2 + 6942^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×866609028² = 1502022414822209568, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 12036201 + ... + 12036272.

Almost surely, 2^866609028 is an apocalyptic number.

It is an amenable number.

866609028 is an abundant number, since it is smaller than the sum of its proper divisors (1323986106).

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

866609028 is a wasteful number, since it uses less digits than its factorization.

866609028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24072483 (or 24072478 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 866609028 is about 29438.2239274043. The cubic root of 866609028 is about 953.3983654378.

The spelling of 866609028 in words is "eight hundred sixty-six million, six hundred nine thousand, twenty-eight".