66993561600 has 672 divisors, whose sum is σ = 260616045696. Its totient is φ = 14863564800.

The previous prime is 66993561589. The next prime is 66993561617. The reversal of 66993561600 is 616539966.

It is a tau number, because it is divible by the number of its divisors (672).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 159129390 + ... + 159129810.

Almost surely, 2^66993561600 is an apocalyptic number.

66993561600 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 66993561600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130308022848).

66993561600 is an abundant number, since it is smaller than the sum of its proper divisors (193622484096).

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

66993561600 is a wasteful number, since it uses less digits than its factorization.

66993561600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504 (or 475 counting only the distinct ones).

The product of its (nonzero) digits is 1574640, while the sum is 51.

The spelling of 66993561600 in words is "sixty-six billion, nine hundred ninety-three million, five hundred sixty-one thousand, six hundred".