205042090 has 32 divisors (see below), whose sum is σ = 403335936. Its totient is φ = 74429760.

The previous prime is 205042081. The next prime is 205042111. The reversal of 205042090 is 90240502.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 79359 + ... + 81901.

It is an arithmetic number, because the mean of its divisors is an integer number (12604248).

Almost surely, 2^205042090 is an apocalyptic number.

205042090 is a deficient number, since it is larger than the sum of its proper divisors (198293846).

205042090 is a wasteful number, since it uses less digits than its factorization.

205042090 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3294.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 205042090 is about 14319.2908343954. The cubic root of 205042090 is about 589.6772054066.

Adding to 205042090 its reverse (90240502), we get a palindrome (295282592).

The spelling of 205042090 in words is "two hundred five million, forty-two thousand, ninety".