66983697893664 has 144 divisors (see below), whose sum is σ = 190591236927000. Its totient is φ = 22315437785088.

The previous prime is 66983697893639. The next prime is 66983697893677. The reversal of 66983697893664 is 46639879638966.

66983697893664 is a `hidden beast` number, since 6 + 6 + 9 + 83 + 6 + 97 + 89 + 366 + 4 = 666.

66983697893664 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 26281084274064 + 40702613619600 = 5126508^2 + 6379860^2 .

It is a tau number, because it is divible by the number of its divisors (144).

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 23 ways as a sum of consecutive naturals, for example, 6913370932 + ... + 6913380620.

Almost surely, 2^{66983697893664} is an apocalyptic number.

It is an amenable number.

66983697893664 is an abundant number, since it is smaller than the sum of its proper divisors (123607539033336).

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

66983697893664 is a wasteful number, since it uses less digits than its factorization.

66983697893664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20627 (or 20616 counting only the distinct ones).

The product of its digits is 91424858112, while the sum is 90.

The spelling of 66983697893664 in words is "sixty-six trillion, nine hundred eighty-three billion, six hundred ninety-seven million, eight hundred ninety-three thousand, six hundred sixty-four".