66688822778886 has 512 divisors, whose sum is σ = 200843919360000. Its totient is φ = 15874417065600.

The previous prime is 66688822778843. The next prime is 66688822778947. The reversal of 66688822778886 is 68887722888666.

It is a junction number, because it is equal to n+sod(n) for n = 66688822778796 and 66688822778805.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 9666444265 + ... + 9666451163.

It is an arithmetic number, because the mean of its divisors is an integer number (392273280000).

Almost surely, 2^{66688822778886} is an apocalyptic number.

66688822778886 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 66688822778886, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (100421959680000).

66688822778886 is an abundant number, since it is smaller than the sum of its proper divisors (134155096581114).

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

66688822778886 is a wasteful number, since it uses less digits than its factorization.

66688822778886 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10925 (or 10919 counting only the distinct ones).

The product of its digits is 66588770304, while the sum is 90.

The spelling of 66688822778886 in words is "sixty-six trillion, six hundred eighty-eight billion, eight hundred twenty-two million, seven hundred seventy-eight thousand, eight hundred eighty-six".