855999 has 6 divisors (see below), whose sum is σ = 1236456. Its totient is φ = 570660.

The previous prime is 855997. The next prime is 856021. The reversal of 855999 is 999558.

855999 is a `hidden beast` number, since 8 + 559 + 99 = 666.

It is not a de Polignac number, because 855999 - 2¹ = 855997 is a prime.

855999 is a modest number, since divided by 999 gives 855 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (855997) 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, 47547 + ... + 47564.

It is an arithmetic number, because the mean of its divisors is an integer number (206076).

2⁸⁵⁵⁹⁹⁹ is an apocalyptic number.

855999 is a deficient number, since it is larger than the sum of its proper divisors (380457).

855999 is a wasteful number, since it uses less digits than its factorization.

855999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95117 (or 95114 counting only the distinct ones).

The product of its digits is 145800, while the sum is 45.

The square root of 855999 is about 925.2021400753. The cubic root of 855999 is about 94.9491509965.

It can be divided in two parts, 85 and 5999, that added together give a square (6084 = 78²).

The spelling of 855999 in words is "eight hundred fifty-five thousand, nine hundred ninety-nine".