855891 has 12 divisors (see below), whose sum is σ = 1257360. Its totient is φ = 560880.

The previous prime is 855889. The next prime is 855901. The reversal of 855891 is 198558.

It is not a de Polignac number, because 855891 - 2¹ = 855889 is a prime.

855891 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (855821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 231 + ... + 1328.

It is an arithmetic number, because the mean of its divisors is an integer number (104780).

2⁸⁵⁵⁸⁹¹ is an apocalyptic number.

855891 is a deficient number, since it is larger than the sum of its proper divisors (401469).

855891 is a wasteful number, since it uses less digits than its factorization.

855891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1626 (or 1623 counting only the distinct ones).

The product of its digits is 14400, while the sum is 36.

The square root of 855891 is about 925.1437726105. The cubic root of 855891 is about 94.9451576353.

It can be divided in two parts, 8558 and 91, that added together give a square (8649 = 93²).

The spelling of 855891 in words is "eight hundred fifty-five thousand, eight hundred ninety-one".