66811905216 has 896 divisors, whose sum is σ = 248203110400. Its totient is φ = 17414258688.

The previous prime is 66811905211. The next prime is 66811905217. The reversal of 66811905216 is 61250911866.

66811905216 is a `hidden beast` number, since 6 + 6 + 8 + 119 + 0 + 521 + 6 = 666.

It is not an unprimeable number, because it can be changed into a prime (66811905211) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 688782480 + ... + 688782576.

It is an arithmetic number, because the mean of its divisors is an integer number (277012400).

Almost surely, 2^66811905216 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 66811905216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (124101555200).

66811905216 is an abundant number, since it is smaller than the sum of its proper divisors (181391205184).

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

66811905216 is an equidigital number, since it uses as much as digits as its factorization.

66811905216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 193 (or 165 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The spelling of 66811905216 in words is "sixty-six billion, eight hundred eleven million, nine hundred five thousand, two hundred sixteen".