66684078440 has 48 divisors (see below), whose sum is σ = 174535373700. Its totient is φ = 22863111936.

The previous prime is 66684078437. The next prime is 66684078443. The reversal of 66684078440 is 4487048666.

66684078440 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (66684078437) and next prime (66684078443).

It can be written as a sum of positive squares in 2 ways, for example, as 64360645636 + 2323432804 = 253694^2 + 48202^2 .

It is not an unprimeable number, because it can be changed into a prime (66684078443) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17009285 + ... + 17013204.

Almost surely, 2^66684078440 is an apocalyptic number.

It is an amenable number.

66684078440 is an abundant number, since it is smaller than the sum of its proper divisors (107851295260).

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

66684078440 is a wasteful number, since it uses less digits than its factorization.

66684078440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34022514 (or 34022503 counting only the distinct ones).

The product of its (nonzero) digits is 6193152, while the sum is 53.

The spelling of 66684078440 in words is "sixty-six billion, six hundred eighty-four million, seventy-eight thousand, four hundred forty".