204138 has 24 divisors (see below), whose sum is σ = 482976. Its totient is φ = 61800.

The previous prime is 204137. The next prime is 204143. The reversal of 204138 is 831402.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 204138.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (204133) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 318 + ... + 713.

It is an arithmetic number, because the mean of its divisors is an integer number (20124).

2²⁰⁴¹³⁸ is an apocalyptic number.

204138 is an abundant number, since it is smaller than the sum of its proper divisors (278838).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

204138 is a wasteful number, since it uses less digits than its factorization.

204138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1050 (or 1047 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

The square root of 204138 is about 451.8163343661. The cubic root of 204138 is about 58.8809242554.

Subtracting 204138 from its reverse (831402), we obtain a square (627264 = 792²).

The spelling of 204138 in words is "two hundred four thousand, one hundred thirty-eight".