205709013 has 18 divisors (see below), whose sum is σ = 304581602. Its totient is φ = 133784640.

The previous prime is 205709003. The next prime is 205709017. The reversal of 205709013 is 310907502.

205709013 is a `hidden beast` number, since 2 + 0 + 570 + 90 + 1 + 3 = 666.

It can be written as a sum of positive squares in 3 ways, for example, as 32970564 + 172738449 = 5742^2 + 13143^2 .

It is not a de Polignac number, because 205709013 - 2⁵ = 205708981 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205709017) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 8331 + ... + 21927.

Almost surely, 2^205709013 is an apocalyptic number.

It is an amenable number.

205709013 is a deficient number, since it is larger than the sum of its proper divisors (98872589).

205709013 is a wasteful number, since it uses less digits than its factorization.

205709013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13685 (or 13641 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 27.

The square root of 205709013 is about 14342.5594996151. The cubic root of 205709013 is about 590.3158444865.

The spelling of 205709013 in words is "two hundred five million, seven hundred nine thousand, thirteen".