66893664978 has 24 divisors (see below), whose sum is σ = 165641456448. Its totient is φ = 19112475672.

The previous prime is 66893664953. The next prime is 66893664983. The reversal of 66893664978 is 87946639866.

66893664978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 265450926 + ... + 265451177.

It is an arithmetic number, because the mean of its divisors is an integer number (6901727352).

Almost surely, 2^66893664978 is an apocalyptic number.

66893664978 is an abundant number, since it is smaller than the sum of its proper divisors (98747791470).

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

66893664978 is a wasteful number, since it uses less digits than its factorization.

66893664978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 530902118 (or 530902115 counting only the distinct ones).

The product of its digits is 564350976, while the sum is 72.

The spelling of 66893664978 in words is "sixty-six billion, eight hundred ninety-three million, six hundred sixty-four thousand, nine hundred seventy-eight".