66665588556666 has 64 divisors (see below), whose sum is σ = 150708381027840. Its totient is φ = 19484588235840.

The previous prime is 66665588556599. The next prime is 66665588556731.

66665588556666 is nontrivially palindromic in base 10.

It is a zygodrome in base 10.

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, 161303800 + ... + 161716563.

It is an arithmetic number, because the mean of its divisors is an integer number (2354818453560).

Almost surely, 2^{66665588556666} is an apocalyptic number.

66665588556666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

66665588556666 is an abundant number, since it is smaller than the sum of its proper divisors (84042792471174).

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

66665588556666 is a wasteful number, since it uses less digits than its factorization.

66665588556666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 323020491.

The product of its digits is 67184640000, while the sum is 84.

The spelling of 66665588556666 in words is "sixty-six trillion, six hundred sixty-five billion, five hundred eighty-eight million, five hundred fifty-six thousand, six hundred sixty-six".