216666684 has 48 divisors (see below), whose sum is σ = 604942240. Its totient is φ = 66666240.

The previous prime is 216666661. The next prime is 216666691. The reversal of 216666684 is 486666612.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 75757 + ... + 78564.

Almost surely, 2^216666684 is an apocalyptic number.

It is an amenable number.

216666684 is an abundant number, since it is smaller than the sum of its proper divisors (388275556).

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

216666684 is a wasteful number, since it uses less digits than its factorization.

216666684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154347 (or 154339 counting only the distinct ones).

The product of its digits is 497664, while the sum is 45.

The square root of 216666684 is about 14719.6020326638. The cubic root of 216666684 is about 600.6166659880.

The spelling of 216666684 in words is "two hundred sixteen million, six hundred sixty-six thousand, six hundred eighty-four".