66728385828 has 36 divisors (see below), whose sum is σ = 181649496028. Its totient is φ = 20531810880.

The previous prime is 66728385797. The next prime is 66728385859. The reversal of 66728385828 is 82858382766.

It is an interprime number because it is at equal distance from previous prime (66728385797) and next prime (66728385859).

It can be written as a sum of positive squares in 2 ways, for example, as 20568722724 + 46159663104 = 143418^2 + 214848^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 71290543 + ... + 71291478.

Almost surely, 2^66728385828 is an apocalyptic number.

It is an amenable number.

66728385828 is an abundant number, since it is smaller than the sum of its proper divisors (114921110200).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66728385828 is a wasteful number, since it uses less digits than its factorization.

66728385828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 142582044 (or 142582039 counting only the distinct ones).

The product of its digits is 61931520, while the sum is 63.

The spelling of 66728385828 in words is "sixty-six billion, seven hundred twenty-eight million, three hundred eighty-five thousand, eight hundred twenty-eight".