805905 has 12 divisors (see below), whose sum is σ = 1396980. Its totient is φ = 429792.

The previous prime is 805901. The next prime is 805913. The reversal of 805905 is 509508.

It can be written as a sum of positive squares in 2 ways, for example, as 321489 + 484416 = 567^2 + 696^2 .

It is not a de Polignac number, because 805905 - 2² = 805901 is a prime.

It is a zygodrome in base 3.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 805905.

It is not an unprimeable number, because it can be changed into a prime (805901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8910 + ... + 8999.

It is an arithmetic number, because the mean of its divisors is an integer number (116415).

2⁸⁰⁵⁹⁰⁵ is an apocalyptic number.

It is an amenable number.

805905 is a deficient number, since it is larger than the sum of its proper divisors (591075).

805905 is a wasteful number, since it uses less digits than its factorization.

805905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17920 (or 17917 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The square root of 805905 is about 897.7221173615. The cubic root of 805905 is about 93.0596218449.

The spelling of 805905 in words is "eight hundred five thousand, nine hundred five".