205128566 has 4 divisors (see below), whose sum is σ = 307692852. Its totient is φ = 102564282.

The previous prime is 205128509. The next prime is 205128569. The reversal of 205128566 is 665821502.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (205128569) by changing a digit.

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 as a sum of consecutive naturals, namely, 51282140 + ... + 51282143.

It is an arithmetic number, because the mean of its divisors is an integer number (76923213).

Almost surely, 2^205128566 is an apocalyptic number.

205128566 is a deficient number, since it is larger than the sum of its proper divisors (102564286).

205128566 is a wasteful number, since it uses less digits than its factorization.

205128566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102564285.

The product of its (nonzero) digits is 28800, while the sum is 35.

The square root of 205128566 is about 14322.3100790340. The cubic root of 205128566 is about 589.7600920617.

The spelling of 205128566 in words is "two hundred five million, one hundred twenty-eight thousand, five hundred sixty-six".