205504405 has 4 divisors (see below), whose sum is σ = 246605292. Its totient is φ = 164403520.

The previous prime is 205504393. The next prime is 205504427. The reversal of 205504405 is 504405502.

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

It can be written as a sum of positive squares in 2 ways, for example, as 160224964 + 45279441 = 12658^2 + 6729^2 .

It is a de Polignac number, because none of the positive numbers 2^k-205504405 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 205504405.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20550436 + ... + 20550445.

It is an arithmetic number, because the mean of its divisors is an integer number (61651323).

Almost surely, 2^205504405 is an apocalyptic number.

It is an amenable number.

205504405 is a deficient number, since it is larger than the sum of its proper divisors (41100887).

205504405 is an equidigital number, since it uses as much as digits as its factorization.

205504405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41100886.

The product of its (nonzero) digits is 4000, while the sum is 25.

The square root of 205504405 is about 14335.4248280265. The cubic root of 205504405 is about 590.1200607914.

Adding to 205504405 its reverse (504405502), we get a palindrome (709909907).

The spelling of 205504405 in words is "two hundred five million, five hundred four thousand, four hundred five".