666666684 has 36 divisors (see below), whose sum is σ = 1758456336. Its totient is φ = 212560128.

The previous prime is 666666667. The next prime is 666666691. The reversal of 666666684 is 486666666.

It is a tau number, because it is divible by the number of its divisors (36).

It is a self number, because there is not a number n which added to its sum of digits gives 666666684.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 401749 + ... + 403404.

Almost surely, 2^666666684 is an apocalyptic number.

It is an amenable number.

666666684 is an abundant number, since it is smaller than the sum of its proper divisors (1091789652).

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

666666684 is a wasteful number, since it uses less digits than its factorization.

666666684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805186 (or 805181 counting only the distinct ones).

The product of its digits is 8957952, while the sum is 54.

The square root of 666666684 is about 25819.8893103747. The cubic root of 666666684 is about 873.5804723073.

It can be divided in two parts, 66666 and 6684, that multiplied together give a palindrome (445595544).

The spelling of 666666684 in words is "six hundred sixty-six million, six hundred sixty-six thousand, six hundred eighty-four".