806405 has 4 divisors (see below), whose sum is σ = 967692. Its totient is φ = 645120.

The previous prime is 806389. The next prime is 806447. The reversal of 806405 is 504608.

It is a Cunningham number, because it is equal to 898²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 289444 + 516961 = 538^2 + 719^2 .

It is not a de Polignac number, because 806405 - 2⁴ = 806389 is a prime.

It is a Duffinian number.

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 806405.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80636 + ... + 80645.

It is an arithmetic number, because the mean of its divisors is an integer number (241923).

2⁸⁰⁶⁴⁰⁵ is an apocalyptic number.

It is an amenable number.

806405 is a deficient number, since it is larger than the sum of its proper divisors (161287).

806405 is a wasteful number, since it uses less digits than its factorization.

806405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 161286.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 806405 is about 898.0005567927. Note that the first 3 decimals coincide. The cubic root of 806405 is about 93.0788632325.

The spelling of 806405 in words is "eight hundred six thousand, four hundred five".