855591 has 12 divisors (see below), whose sum is σ = 1254456. Its totient is φ = 518320.

The previous prime is 855581. The next prime is 855601. The reversal of 855591 is 195558.

855591 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (855581) and next prime (855601).

It is not a de Polignac number, because 855591 - 2⁶ = 855527 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (855511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 816 + ... + 1541.

It is an arithmetic number, because the mean of its divisors is an integer number (104538).

2⁸⁵⁵⁵⁹¹ is an apocalyptic number.

855591 is a deficient number, since it is larger than the sum of its proper divisors (398865).

855591 is a wasteful number, since it uses less digits than its factorization.

855591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2382 (or 2371 counting only the distinct ones).

The product of its digits is 9000, while the sum is 33.

The square root of 855591 is about 924.9816214390. The cubic root of 855591 is about 94.9340632023.

Subtracting from 855591 its sum of digits (33), we obtain a palindrome (855558).

It can be divided in two parts, 8555 and 91, that added together give a triangular number (8646 = T₁₃₁).

The spelling of 855591 in words is "eight hundred fifty-five thousand, five hundred ninety-one".