66904978688 has 18 divisors (see below), whose sum is σ = 133548610314. Its totient is φ = 33452489216.

The previous prime is 66904978633. The next prime is 66904978697. The reversal of 66904978688 is 88687940966.

66904978688 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 only one way, i.e., 54920859904 + 11984118784 = 234352^2 + 109472^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 130673531 + ... + 130674042.

Almost surely, 2^66904978688 is an apocalyptic number.

It is an amenable number.

66904978688 is a deficient number, since it is larger than the sum of its proper divisors (66643631626).

66904978688 is an equidigital number, since it uses as much as digits as its factorization.

66904978688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261347589 (or 261347575 counting only the distinct ones).

The product of its (nonzero) digits is 250822656, while the sum is 71.

The spelling of 66904978688 in words is "sixty-six billion, nine hundred four million, nine hundred seventy-eight thousand, six hundred eighty-eight".