865138806 has 144 divisors (see below), whose sum is σ = 2395398096. Its totient is φ = 232533504.

The previous prime is 865138753. The next prime is 865138819. The reversal of 865138806 is 608831568.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 403770 + ... + 405906.

It is an arithmetic number, because the mean of its divisors is an integer number (16634709).

Almost surely, 2^865138806 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 865138806, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1197699048).

865138806 is an abundant number, since it is smaller than the sum of its proper divisors (1530259290).

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

865138806 is a wasteful number, since it uses less digits than its factorization.

865138806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2185 (or 2166 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The square root of 865138806 is about 29413.2420178395. The cubic root of 865138806 is about 952.8589062236.

The spelling of 865138806 in words is "eight hundred sixty-five million, one hundred thirty-eight thousand, eight hundred six".