204538639 has 4 divisors (see below), whose sum is σ = 206010280. Its totient is φ = 203067000.

The previous prime is 204538637. The next prime is 204538687. The reversal of 204538639 is 936835402.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 204538639 - 2¹ = 204538637 is a prime.

It is a super-3 number, since 3×204538639³ (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 (204538637) 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 3 ways as a sum of consecutive naturals, for example, 735612 + ... + 735889.

It is an arithmetic number, because the mean of its divisors is an integer number (51502570).

Almost surely, 2^204538639 is an apocalyptic number.

204538639 is a deficient number, since it is larger than the sum of its proper divisors (1471641).

204538639 is a wasteful number, since it uses less digits than its factorization.

204538639 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1471640.

The product of its (nonzero) digits is 155520, while the sum is 40.

The square root of 204538639 is about 14301.7005632197. The cubic root of 204538639 is about 589.1941876884.

It can be divided in two parts, 20453 and 8639, that added together give a palindrome (29092).

The spelling of 204538639 in words is "two hundred four million, five hundred thirty-eight thousand, six hundred thirty-nine".