165806 has 4 divisors (see below), whose sum is σ = 248712. Its totient is φ = 82902.

The previous prime is 165799. The next prime is 165811. The reversal of 165806 is 608561.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

165806 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41450 + ... + 41453.

It is an arithmetic number, because the mean of its divisors is an integer number (62178).

2¹⁶⁵⁸⁰⁶ is an apocalyptic number.

165806 is a deficient number, since it is larger than the sum of its proper divisors (82906).

165806 is an equidigital number, since it uses as much as digits as its factorization.

165806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82905.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 165806 is about 407.1928290135. The cubic root of 165806 is about 54.9372286620.

The spelling of 165806 in words is "one hundred sixty-five thousand, eight hundred six".