66777777788 has 12 divisors (see below), whose sum is σ = 116863519920. Its totient is φ = 33388200672.

The previous prime is 66777777779. The next prime is 66777777791. The reversal of 66777777788 is 88777777766.

It is a plaindrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 90920 + ... + 376592.

It is an arithmetic number, because the mean of its divisors is an integer number (9738626660).

Almost surely, 2^66777777788 is an apocalyptic number.

It is an amenable number.

66777777788 is a deficient number, since it is larger than the sum of its proper divisors (50085742132).

66777777788 is a wasteful number, since it uses less digits than its factorization.

66777777788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 344116 (or 344114 counting only the distinct ones).

The product of its digits is 1897443072, while the sum is 77.

The spelling of 66777777788 in words is "sixty-six billion, seven hundred seventy-seven million, seven hundred seventy-seven thousand, seven hundred eighty-eight".