205342209 has 10 divisors (see below), whose sum is σ = 306745890. Its totient is φ = 136894752.

The previous prime is 205342199. The next prime is 205342213. The reversal of 205342209 is 902243502.

It can be written as a sum of positive squares in only one way, i.e., 205291584 + 50625 = 14328^2 + 225^2 .

It is not a de Polignac number, because 205342209 - 2¹⁵ = 205309441 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (205342259) 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 9 ways as a sum of consecutive naturals, for example, 1267464 + ... + 1267625.

It is an arithmetic number, because the mean of its divisors is an integer number (30674589).

Almost surely, 2^205342209 is an apocalyptic number.

It is an amenable number.

205342209 is a deficient number, since it is larger than the sum of its proper divisors (101403681).

205342209 is an equidigital number, since it uses as much as digits as its factorization.

205342209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2535101 (or 2535092 counting only the distinct ones).

The product of its (nonzero) digits is 4320, while the sum is 27.

The square root of 205342209 is about 14329.7665368282. The cubic root of 205342209 is about 589.9647675983.

The spelling of 205342209 in words is "two hundred five million, three hundred forty-two thousand, two hundred nine".