204690209 has 4 divisors (see below), whose sum is σ = 204718980. Its totient is φ = 204661440.

The previous prime is 204690169. The next prime is 204690229. The reversal of 204690209 is 902096402.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 167443600 + 37246609 = 12940^2 + 6103^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-204690209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (204690229) 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, 4949 + ... + 20829.

It is an arithmetic number, because the mean of its divisors is an integer number (51179745).

Almost surely, 2^204690209 is an apocalyptic number.

It is an amenable number.

204690209 is a deficient number, since it is larger than the sum of its proper divisors (28771).

204690209 is a wasteful number, since it uses less digits than its factorization.

204690209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28770.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 204690209 is about 14306.9986020828. The cubic root of 204690209 is about 589.3396893133.

The spelling of 204690209 in words is "two hundred four million, six hundred ninety thousand, two hundred nine".