866660660 has 12 divisors (see below), whose sum is σ = 1819987428. Its totient is φ = 346664256.

The previous prime is 866660659. The next prime is 866660671. The reversal of 866660660 is 66066668.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 296597284 + 570063376 = 17222^2 + 23876^2 .

It is a super-2 number, since 2×866660660² = 1502201399183271200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 21666497 + ... + 21666536.

It is an arithmetic number, because the mean of its divisors is an integer number (151665619).

Almost surely, 2^866660660 is an apocalyptic number.

It is an amenable number.

866660660 is an abundant number, since it is smaller than the sum of its proper divisors (953326768).

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

866660660 is a wasteful number, since it uses less digits than its factorization.

866660660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 43333042 (or 43333040 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 44.

The square root of 866660660 is about 29439.1008694219. The cubic root of 866660660 is about 953.4172993458.

The spelling of 866660660 in words is "eight hundred sixty-six million, six hundred sixty thousand, six hundred sixty".