66781440000 has 1440 divisors, whose sum is σ = 287377009920. Its totient is φ = 14745600000.

The previous prime is 66781439999. The next prime is 66781440001. The reversal of 66781440000 is 4418766.

It is an interprime number because it is at equal distance from previous prime (66781439999) and next prime (66781440001).

It is a tau number, because it is divible by the number of its divisors (1440).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (66781440001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 2154239985 + ... + 2154240015.

It is an arithmetic number, because the mean of its divisors is an integer number (199567368).

Almost surely, 2^66781440000 is an apocalyptic number.

66781440000 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 66781440000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143688504960).

66781440000 is an abundant number, since it is smaller than the sum of its proper divisors (220595569920).

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

66781440000 is a wasteful number, since it uses less digits than its factorization.

66781440000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107 (or 69 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

Adding to 66781440000 its reverse (4418766), we get a palindrome (66785858766).

The spelling of 66781440000 in words is "sixty-six billion, seven hundred eighty-one million, four hundred forty thousand".