66538844064 has 768 divisors, whose sum is σ = 250195599360. Its totient is φ = 16706027520.

The previous prime is 66538844051. The next prime is 66538844107. The reversal of 66538844064 is 46044883566.

66538844064 is a `hidden beast` number, since 6 + 6 + 538 + 8 + 4 + 40 + 64 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 66538844064.

It is an unprimeable number.

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 127 ways as a sum of consecutive naturals, for example, 398436109 + ... + 398436275.

It is an arithmetic number, because the mean of its divisors is an integer number (325775520).

Almost surely, 2^66538844064 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 66538844064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125097799680).

66538844064 is an abundant number, since it is smaller than the sum of its proper divisors (183656755296).

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

66538844064 is a wasteful number, since it uses less digits than its factorization.

66538844064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370 (or 356 counting only the distinct ones).

The product of its (nonzero) digits is 13271040, while the sum is 54.

The spelling of 66538844064 in words is "sixty-six billion, five hundred thirty-eight million, eight hundred forty-four thousand, sixty-four".