856638 has 12 divisors (see below), whose sum is σ = 1856088. Its totient is φ = 285540.

The previous prime is 856637. The next prime is 856649. The reversal of 856638 is 836658.

856638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (856637) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23778 + ... + 23813.

It is an arithmetic number, because the mean of its divisors is an integer number (154674).

2⁸⁵⁶⁶³⁸ is an apocalyptic number.

856638 is an abundant number, since it is smaller than the sum of its proper divisors (999450).

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

856638 is a wasteful number, since it uses less digits than its factorization.

856638 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47599 (or 47596 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 856638 is about 925.5474055930. The cubic root of 856638 is about 94.9727715133.

Adding to 856638 its product of digits (34560), we get a palindrome (891198).

The spelling of 856638 in words is "eight hundred fifty-six thousand, six hundred thirty-eight".