205439 has 4 divisors (see below), whose sum is σ = 221256. Its totient is φ = 189624.

The previous prime is 205433. The next prime is 205441. The reversal of 205439 is 934502.

205439 = T₃₀ + T₃₁ + ... + T₁₀₇.

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

It is a cyclic number.

It is not a de Polignac number, because 205439 - 2⁴ = 205423 is a prime.

It is a d-powerful number, because it can be written as 2¹³ + 0 + 4⁵ + 5⁷ + 3¹⁰ + 9⁵ .

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7889 + ... + 7914.

It is an arithmetic number, because the mean of its divisors is an integer number (55314).

2²⁰⁵⁴³⁹ is an apocalyptic number.

205439 is a deficient number, since it is larger than the sum of its proper divisors (15817).

205439 is a wasteful number, since it uses less digits than its factorization.

205439 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15816.

The product of its (nonzero) digits is 1080, while the sum is 23.

The square root of 205439 is about 453.2537920415. The cubic root of 205439 is about 59.0057449160.

The spelling of 205439 in words is "two hundred five thousand, four hundred thirty-nine".