205505123 has 4 divisors (see below), whose sum is σ = 205535568. Its totient is φ = 205474680.

The previous prime is 205505101. The next prime is 205505137. The reversal of 205505123 is 321505502.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 205505123 - 2⁶ = 205505059 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (205505173) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68 + ... + 20273.

It is an arithmetic number, because the mean of its divisors is an integer number (51383892).

Almost surely, 2^205505123 is an apocalyptic number.

205505123 is a deficient number, since it is larger than the sum of its proper divisors (30445).

205505123 is a wasteful number, since it uses less digits than its factorization.

205505123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30444.

The product of its (nonzero) digits is 1500, while the sum is 23.

The square root of 205505123 is about 14335.4498708621. The cubic root of 205505123 is about 590.1207480527.

The spelling of 205505123 in words is "two hundred five million, five hundred five thousand, one hundred twenty-three".