66520440828 has 72 divisors (see below), whose sum is σ = 172924752000. Its totient is φ = 21548884896.

The previous prime is 66520440823. The next prime is 66520440839. The reversal of 66520440828 is 82804402566.

66520440828 is a `hidden beast` number, since 6 + 6 + 520 + 4 + 40 + 82 + 8 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66520440823) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 200083 + ... + 416021.

Almost surely, 2^66520440828 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66520440828, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (86462376000).

66520440828 is an abundant number, since it is smaller than the sum of its proper divisors (106404311172).

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

66520440828 is a wasteful number, since it uses less digits than its factorization.

66520440828 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216191 (or 216186 counting only the distinct ones).

The product of its (nonzero) digits is 737280, while the sum is 45.

The spelling of 66520440828 in words is "sixty-six billion, five hundred twenty million, four hundred forty thousand, eight hundred twenty-eight".