666884707488666 has 12 divisors (see below), whose sum is σ = 1444916866225482. Its totient is φ = 222294902496216.

The previous prime is 666884707488661. The next prime is 666884707488719.

666884707488666 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in only one way, i.e., 666658199075625 + 226508413041 = 25819725^2 + 475929^2 .

It is a super-2 number, since 2×666884707488666² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (666884707488661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 18524575208001 + ... + 18524575208036.

Almost surely, 2^{666884707488666} is an apocalyptic number.

666884707488666 is an abundant number, since it is smaller than the sum of its proper divisors (778032158736816).

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

666884707488666 is a wasteful number, since it uses less digits than its factorization.

666884707488666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37049150416045 (or 37049150416042 counting only the distinct ones).

The product of its (nonzero) digits is 149824733184, while the sum is 90.

The spelling of 666884707488666 in words is "six hundred sixty-six trillion, eight hundred eighty-four billion, seven hundred seven million, four hundred eighty-eight thousand, six hundred sixty-six".