9855128529 has 9 divisors (see below), whose sum is σ = 14235615849. Its totient is φ = 6569887140.

The previous prime is 9855128489. The next prime is 9855128533. The reversal of 9855128529 is 9258215589.

The square root of 9855128529 is 99273.

It is a perfect power (a square), and thus also a powerful number.

9855128529 is a `hidden beast` number, since 9 + 8 + 551 + 2 + 85 + 2 + 9 = 666.

9855128529 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 9855128529 - 2²⁵ = 9821574097 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9855128539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 281274 + ... + 314364.

Almost surely, 2^9855128529 is an apocalyptic number.

9855128529 is the 99273-rd square number.

9855128529 is the 49637-th centered octagonal number.

It is an amenable number.

9855128529 is a deficient number, since it is larger than the sum of its proper divisors (4380487320).

9855128529 is an frugal number, since it uses more digits than its factorization.

9855128529 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 66188 (or 33094 counting only the distinct ones).

The product of its digits is 2592000, while the sum is 54.

The cubic root of 9855128529 is about 2143.9801701665.

It can be divided in two parts, 9855 and 128529, that added together give a square (138384 = 372²).

The spelling of 9855128529 in words is "nine billion, eight hundred fifty-five million, one hundred twenty-eight thousand, five hundred twenty-nine".