66681302688 has 864 divisors, whose sum is σ = 262010391552. Its totient is φ = 15811891200.

The previous prime is 66681302621. The next prime is 66681302729. The reversal of 66681302688 is 88620318666.

66681302688 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×66681302688² (a number of 22 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 349116673 + ... + 349116863.

It is an arithmetic number, because the mean of its divisors is an integer number (303252768).

Almost surely, 2^66681302688 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 66681302688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (131005195776).

66681302688 is an abundant number, since it is smaller than the sum of its proper divisors (195329088864).

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

66681302688 is a wasteful number, since it uses less digits than its factorization.

66681302688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418 (or 400 counting only the distinct ones).

The product of its (nonzero) digits is 3981312, while the sum is 54.

The spelling of 66681302688 in words is "sixty-six billion, six hundred eighty-one million, three hundred two thousand, six hundred eighty-eight".