66659344640 has 576 divisors, whose sum is σ = 210226544640. Its totient is φ = 19694223360.

The previous prime is 66659344613. The next prime is 66659344643. The reversal of 66659344640 is 4644395666.

It is not an unprimeable number, because it can be changed into a prime (66659344643) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 89716109 + ... + 89716851.

It is an arithmetic number, because the mean of its divisors is an integer number (364976640).

Almost surely, 2^66659344640 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 66659344640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105113272320).

66659344640 is an abundant number, since it is smaller than the sum of its proper divisors (143567200000).

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

66659344640 is a wasteful number, since it uses less digits than its factorization.

66659344640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 838 (or 824 counting only the distinct ones).

The product of its (nonzero) digits is 11197440, while the sum is 53.

The spelling of 66659344640 in words is "sixty-six billion, six hundred fifty-nine million, three hundred forty-four thousand, six hundred forty".