66544038064 has 80 divisors (see below), whose sum is σ = 150364304640. Its totient is φ = 27936679680.

The previous prime is 66544038037. The next prime is 66544038073. The reversal of 66544038064 is 46083044566.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3903319 + ... + 3920329.

It is an arithmetic number, because the mean of its divisors is an integer number (1879553808).

Almost surely, 2^66544038064 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 66544038064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (75182152320).

66544038064 is an abundant number, since it is smaller than the sum of its proper divisors (83820266576).

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

66544038064 is a wasteful number, since it uses less digits than its factorization.

66544038064 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17738 (or 17732 counting only the distinct ones).

The product of its (nonzero) digits is 1658880, while the sum is 46.

The spelling of 66544038064 in words is "sixty-six billion, five hundred forty-four million, thirty-eight thousand, sixty-four".