66798785664 has 384 divisors, whose sum is σ = 211065254400. Its totient is φ = 20155392000.

The previous prime is 66798785639. The next prime is 66798785693. The reversal of 66798785664 is 46658789766.

It is a tau number, because it is divible by the number of its divisors (384).

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a junction number, because it is equal to n+sod(n) for n = 66798785592 and 66798785601.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 246489849 + ... + 246490119.

It is an arithmetic number, because the mean of its divisors is an integer number (549649100).

Almost surely, 2^66798785664 is an apocalyptic number.

66798785664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66798785664, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (105532627200).

66798785664 is an abundant number, since it is smaller than the sum of its proper divisors (144266468736).

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

66798785664 is a wasteful number, since it uses less digits than its factorization.

66798785664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 564 (or 549 counting only the distinct ones).

The product of its digits is 731566080, while the sum is 72.

The spelling of 66798785664 in words is "sixty-six billion, seven hundred ninety-eight million, seven hundred eighty-five thousand, six hundred sixty-four".