866136321 has 24 divisors (see below), whose sum is σ = 1298990784. Its totient is φ = 576726480.

The previous prime is 866136251. The next prime is 866136353. The reversal of 866136321 is 123631668.

866136321 is a `hidden beast` number, since 8 + 6 + 6 + 13 + 632 + 1 = 666.

It is not a de Polignac number, because 866136321 - 2¹¹ = 866134273 is a prime.

It is not an unprimeable number, because it can be changed into a prime (866136361) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 269836 + ... + 273026.

It is an arithmetic number, because the mean of its divisors is an integer number (54124616).

Almost surely, 2^866136321 is an apocalyptic number.

866136321 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

866136321 is a deficient number, since it is larger than the sum of its proper divisors (432854463).

866136321 is a wasteful number, since it uses less digits than its factorization.

866136321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4323 (or 4311 counting only the distinct ones).

The product of its digits is 31104, while the sum is 36.

The square root of 866136321 is about 29430.1940360576. The cubic root of 866136321 is about 953.2249846572.

Adding to 866136321 its reverse (123631668), we get a palindrome (989767989).

The spelling of 866136321 in words is "eight hundred sixty-six million, one hundred thirty-six thousand, three hundred twenty-one".