805665 has 16 divisors (see below), whose sum is σ = 1473408. Its totient is φ = 368256.

The previous prime is 805639. The next prime is 805687. The reversal of 805665 is 566508.

805665 = 203² + 204² + ... + 220².

It is not a de Polignac number, because 805665 - 2⁵ = 805633 is a prime.

It is a Curzon number.

805665 is a lucky 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 805665.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3732 + ... + 3941.

It is an arithmetic number, because the mean of its divisors is an integer number (92088).

2⁸⁰⁵⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

805665 is a deficient number, since it is larger than the sum of its proper divisors (667743).

805665 is a wasteful number, since it uses less digits than its factorization.

805665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7688.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 805665 is about 897.5884357544. The cubic root of 805665 is about 93.0503831519.

The spelling of 805665 in words is "eight hundred five thousand, six hundred sixty-five".