204109813 has 4 divisors (see below), whose sum is σ = 204138508. Its totient is φ = 204081120.

The previous prime is 204109811. The next prime is 204109853. The reversal of 204109813 is 318901402.

It is a happy number.

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 176305284 + 27804529 = 13278^2 + 5273^2 .

It is a cyclic number.

It is not a de Polignac number, because 204109813 - 2¹ = 204109811 is a prime.

It is a super-3 number, since 3×204109813³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204109811) 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, 5203 + ... + 20863.

It is an arithmetic number, because the mean of its divisors is an integer number (51034627).

Almost surely, 2^204109813 is an apocalyptic number.

It is an amenable number.

204109813 is a deficient number, since it is larger than the sum of its proper divisors (28695).

204109813 is a wasteful number, since it uses less digits than its factorization.

204109813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28694.

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 204109813 is about 14286.7005638111. The cubic root of 204109813 is about 588.7821407408.

The spelling of 204109813 in words is "two hundred four million, one hundred nine thousand, eight hundred thirteen".