205459309 has 4 divisors (see below), whose sum is σ = 224137440. Its totient is φ = 186781180.

The previous prime is 205459307. The next prime is 205459321. The reversal of 205459309 is 903954502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 205459309 - 2¹ = 205459307 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 (205459301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9339049 + ... + 9339070.

It is an arithmetic number, because the mean of its divisors is an integer number (56034360).

Almost surely, 2^205459309 is an apocalyptic number.

It is an amenable number.

205459309 is a deficient number, since it is larger than the sum of its proper divisors (18678131).

205459309 is a wasteful number, since it uses less digits than its factorization.

205459309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18678130.

The product of its (nonzero) digits is 48600, while the sum is 37.

The square root of 205459309 is about 14333.8518549621. The cubic root of 205459309 is about 590.0768922097.

The spelling of 205459309 in words is "two hundred five million, four hundred fifty-nine thousand, three hundred nine".