66478734081680 has 40 divisors (see below), whose sum is σ = 156680358900792. Its totient is φ = 26227226594304.

The previous prime is 66478734081673. The next prime is 66478734081703. The reversal of 66478734081680 is 8618043787466.

It is a happy number.

66478734081680 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 69729796096 + 66409004285584 = 264064^2 + 8149172^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 66478734081680.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5691666599 + ... + 5691678278.

Almost surely, 2^{66478734081680} is an apocalyptic number.

It is an amenable number.

66478734081680 is an abundant number, since it is smaller than the sum of its proper divisors (90201624819112).

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

66478734081680 is a wasteful number, since it uses less digits than its factorization.

66478734081680 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11383344963 (or 11383344957 counting only the distinct ones).

The product of its (nonzero) digits is 260112384, while the sum is 68.

The spelling of 66478734081680 in words is "sixty-six trillion, four hundred seventy-eight billion, seven hundred thirty-four million, eighty-one thousand, six hundred eighty".