It is a tau number, because it is divible by the number of its divisors (128).
It is an unprimeable number.
Almost surely, 266635781934208 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 66635781934208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (67579157520000).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
66635781934208 is a wasteful number, since it uses less digits than its factorization.
66635781934208 is an evil number, because the sum of its binary digits is even.
The spelling of 66635781934208 in words is "sixty-six trillion, six hundred thirty-five billion, seven hundred eighty-one million, nine hundred thirty-four thousand, two hundred eight".