865806638 has 8 divisors (see below), whose sum is σ = 1300427832. Its totient is φ = 432330696.

The previous prime is 865806637. The next prime is 865806647. The reversal of 865806638 is 836608568.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-2 number, since 2×865806638² = 1499242268809726088, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865806631) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 284420 + ... + 287447.

It is an arithmetic number, because the mean of its divisors is an integer number (162553479).

Almost surely, 2^865806638 is an apocalyptic number.

865806638 is a deficient number, since it is larger than the sum of its proper divisors (434621194).

865806638 is a wasteful number, since it uses less digits than its factorization.

865806638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 572626.

The product of its (nonzero) digits is 1658880, while the sum is 50.

The square root of 865806638 is about 29424.5924015950. The cubic root of 865806638 is about 953.1040252706.

The spelling of 865806638 in words is "eight hundred sixty-five million, eight hundred six thousand, six hundred thirty-eight".