66665406312 has 144 divisors (see below), whose sum is σ = 183993870060. Its totient is φ = 21805756416.

The previous prime is 66665406289. The next prime is 66665406317. The reversal of 66665406312 is 21360456666.

It can be written as a sum of positive squares in 6 ways, for example, as 57309487236 + 9355919076 = 239394^2 + 96726^2 .

It is not an unprimeable number, because it can be changed into a prime (66665406317) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 112420288 + ... + 112420880.

Almost surely, 2^66665406312 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 66665406312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (91996935030).

66665406312 is an abundant number, since it is smaller than the sum of its proper divisors (117328463748).

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

66665406312 is a wasteful number, since it uses less digits than its factorization.

66665406312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1044 (or 964 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 45.

The spelling of 66665406312 in words is "sixty-six billion, six hundred sixty-five million, four hundred six thousand, three hundred twelve".