666700406691 has 24 divisors (see below), whose sum is σ = 1023471607104. Its totient is φ = 382794485040.

The previous prime is 666700406681. The next prime is 666700406717. The reversal of 666700406691 is 196604007666.

It is not a de Polignac number, because 666700406691 - 2⁷ = 666700406563 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666700406651) 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 23 ways as a sum of consecutive naturals, for example, 27970141 + ... + 27993966.

It is an arithmetic number, because the mean of its divisors is an integer number (42644650296).

Almost surely, 2^666700406691 is an apocalyptic number.

666700406691 is a deficient number, since it is larger than the sum of its proper divisors (356771200413).

666700406691 is a wasteful number, since it uses less digits than its factorization.

666700406691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55964159 (or 55964140 counting only the distinct ones).

The product of its (nonzero) digits is 1959552, while the sum is 51.

The spelling of 666700406691 in words is "six hundred sixty-six billion, seven hundred million, four hundred six thousand, six hundred ninety-one".