66816061866 has 64 divisors (see below), whose sum is σ = 149164848000. Its totient is φ = 22169548800.

The previous prime is 66816061859. The next prime is 66816061891.

66816061866 is a `hidden beast` number, since 6 + 6 + 8 + 16 + 0 + 618 + 6 + 6 = 666.

66816061866 is nontrivially palindromic in base 10.

66816061866 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×66816061866² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12077521 + ... + 12083051.

It is an arithmetic number, because the mean of its divisors is an integer number (2330700750).

Almost surely, 2^66816061866 is an apocalyptic number.

66816061866 is an abundant number, since it is smaller than the sum of its proper divisors (82348786134).

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

66816061866 is a wasteful number, since it uses less digits than its factorization.

66816061866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6532 (or 6526 counting only the distinct ones).

The product of its (nonzero) digits is 2985984, while the sum is 54.

The spelling of 66816061866 in words is "sixty-six billion, eight hundred sixteen million, sixty-one thousand, eight hundred sixty-six".