855865 has 8 divisors (see below), whose sum is σ = 1087560. Its totient is φ = 644352.

The previous prime is 855863. The next prime is 855887. The reversal of 855865 is 568558.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 95481 + 760384 = 309^2 + 872^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 855865 - 2¹ = 855863 is a prime.

855865 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (855863) 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 7 ways as a sum of consecutive naturals, for example, 4950 + ... + 5119.

It is an arithmetic number, because the mean of its divisors is an integer number (135945).

2⁸⁵⁵⁸⁶⁵ is an apocalyptic number.

855865 is a gapful number since it is divisible by the number (85) formed by its first and last digit.

It is an amenable number.

855865 is a deficient number, since it is larger than the sum of its proper divisors (231695).

855865 is a wasteful number, since it uses less digits than its factorization.

855865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10091.

The product of its digits is 48000, while the sum is 37.

The square root of 855865 is about 925.1297206338. The cubic root of 855865 is about 94.9441962204.

The spelling of 855865 in words is "eight hundred fifty-five thousand, eight hundred sixty-five".