66159187812 has 72 divisors (see below), whose sum is σ = 169834739256. Its totient is φ = 21711435264.

The previous prime is 66159187811. The next prime is 66159187813. The reversal of 66159187812 is 21878195166.

It is a happy number.

66159187812 is a `hidden beast` number, since 6 + 615 + 9 + 1 + 8 + 7 + 8 + 12 = 666.

It is an interprime number because it is at equal distance from previous prime (66159187811) and next prime (66159187813).

It can be written as a sum of positive squares in 4 ways, for example, as 12745506816 + 53413680996 = 112896^2 + 231114^2 .

It is not an unprimeable number, because it can be changed into a prime (66159187811) 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, 1441198 + ... + 1486394.

It is an arithmetic number, because the mean of its divisors is an integer number (2358815823).

Almost surely, 2^66159187812 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 66159187812, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (84917369628).

66159187812 is an abundant number, since it is smaller than the sum of its proper divisors (103675551444).

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

66159187812 is a wasteful number, since it uses less digits than its factorization.

66159187812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45837 (or 45832 counting only the distinct ones).

The product of its digits is 1451520, while the sum is 54.

The spelling of 66159187812 in words is "sixty-six billion, one hundred fifty-nine million, one hundred eighty-seven thousand, eight hundred twelve".