66981865600 has 288 divisors, whose sum is σ = 180329239440. Its totient is φ = 24572620800.

The previous prime is 66981865543. The next prime is 66981865651. The reversal of 66981865600 is 656818966.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 114108507 + ... + 114109093.

Almost surely, 2^66981865600 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 66981865600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90164619720).

66981865600 is an abundant number, since it is smaller than the sum of its proper divisors (113347373840).

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

66981865600 is a wasteful number, since it uses less digits than its factorization.

66981865600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 848 (or 818 counting only the distinct ones).

The product of its (nonzero) digits is 3732480, while the sum is 55.

The spelling of 66981865600 in words is "sixty-six billion, nine hundred eighty-one million, eight hundred sixty-five thousand, six hundred".