66709978608 has 160 divisors (see below), whose sum is σ = 214087297536. Its totient is φ = 17429289984.

The previous prime is 66709978603. The next prime is 66709978631. The reversal of 66709978608 is 80687990766.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66709978603) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 396010 + ... + 538742.

Almost surely, 2^66709978608 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66709978608, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (107043648768).

66709978608 is an abundant number, since it is smaller than the sum of its proper divisors (147377318928).

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

66709978608 is a wasteful number, since it uses less digits than its factorization.

66709978608 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142871 (or 142865 counting only the distinct ones).

The product of its (nonzero) digits is 54867456, while the sum is 66.

The spelling of 66709978608 in words is "sixty-six billion, seven hundred nine million, nine hundred seventy-eight thousand, six hundred eight".