205780 has 12 divisors (see below), whose sum is σ = 432180. Its totient is φ = 82304.

The previous prime is 205763. The next prime is 205783. The reversal of 205780 is 87502.

205780 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 133956 + 71824 = 366^2 + 268^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205783) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5125 + ... + 5164.

It is an arithmetic number, because the mean of its divisors is an integer number (36015).

2²⁰⁵⁷⁸⁰ is an apocalyptic number.

205780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

205780 is an abundant number, since it is smaller than the sum of its proper divisors (226400).

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

205780 is a wasteful number, since it uses less digits than its factorization.

205780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10298 (or 10296 counting only the distinct ones).

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 205780 is about 453.6298050173. The cubic root of 205780 is about 59.0383739634.

It can be divided in two parts, 20 and 5780, that multiplied together give a square (115600 = 340²).

The spelling of 205780 in words is "two hundred five thousand, seven hundred eighty".