855509 has 4 divisors (see below), whose sum is σ = 858816. Its totient is φ = 852204.

The previous prime is 855499. The next prime is 855511. The reversal of 855509 is 905558.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 855509 - 2¹² = 851413 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (855709) 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 3 ways as a sum of consecutive naturals, for example, 1229 + ... + 1794.

It is an arithmetic number, because the mean of its divisors is an integer number (214704).

2⁸⁵⁵⁵⁰⁹ is an apocalyptic number.

It is an amenable number.

855509 is a deficient number, since it is larger than the sum of its proper divisors (3307).

855509 is a wasteful number, since it uses less digits than its factorization.

855509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3306.

The product of its (nonzero) digits is 9000, while the sum is 32.

The square root of 855509 is about 924.9372951719. The cubic root of 855509 is about 94.9310302727.

The spelling of 855509 in words is "eight hundred fifty-five thousand, five hundred nine".