205590 has 64 divisors (see below), whose sum is σ = 622080. Its totient is φ = 42240.

The previous prime is 205589. The next prime is 205603. The reversal of 205590 is 95502.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2266 + ... + 2354.

It is an arithmetic number, because the mean of its divisors is an integer number (9720).

2²⁰⁵⁵⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 205590, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (311040).

205590 is an abundant number, since it is smaller than the sum of its proper divisors (416490).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

205590 is a wasteful number, since it uses less digits than its factorization.

205590 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117.

The product of its (nonzero) digits is 450, while the sum is 21.

The square root of 205590 is about 453.4203347888. The cubic root of 205590 is about 59.0201980066.

It can be divided in two parts, 2055 and 90, that added together give a triangular number (2145 = T₆₅).

The spelling of 205590 in words is "two hundred five thousand, five hundred ninety".