66688666800 has 960 divisors, whose sum is σ = 266435328000. Its totient is φ = 14224896000.

The previous prime is 66688666799. The next prime is 66688666823. The reversal of 66688666800 is 866688666.

66688666800 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 2×66688666800² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 441646725 + ... + 441646875.

It is an arithmetic number, because the mean of its divisors is an integer number (277536800).

Almost surely, 2^66688666800 is an apocalyptic number.

66688666800 is a gapful number since it is divisible by the number (60) 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 66688666800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (133217664000).

66688666800 is an abundant number, since it is smaller than the sum of its proper divisors (199746661200).

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

66688666800 is a wasteful number, since it uses less digits than its factorization.

66688666800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 259 (or 234 counting only the distinct ones).

The product of its (nonzero) digits is 23887872, while the sum is 60.

The spelling of 66688666800 in words is "sixty-six billion, six hundred eighty-eight million, six hundred sixty-six thousand, eight hundred".