18205205 has 4 divisors (see below), whose sum is σ = 21846252. Its totient is φ = 14564160.

The previous prime is 18205183. The next prime is 18205237. The reversal of 18205205 is 50250281.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50250281 = 4759 ⋅10559.

It can be written as a sum of positive squares in 2 ways, for example, as 12794929 + 5410276 = 3577^2 + 2326^2 .

It is not a de Polignac number, because 18205205 - 2⁶ = 18205141 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

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, 1820516 + ... + 1820525.

It is an arithmetic number, because the mean of its divisors is an integer number (5461563).

Almost surely, 2^18205205 is an apocalyptic number.

It is an amenable number.

18205205 is a deficient number, since it is larger than the sum of its proper divisors (3641047).

18205205 is an equidigital number, since it uses as much as digits as its factorization.

18205205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3641046.

The product of its (nonzero) digits is 800, while the sum is 23.

The square root of 18205205 is about 4266.7557933399. The cubic root of 18205205 is about 263.0662846705.

Adding to 18205205 its reverse (50250281), we get a palindrome (68455486).

The spelling of 18205205 in words is "eighteen million, two hundred five thousand, two hundred five".