666216684 has 96 divisors (see below), whose sum is σ = 2077913600. Its totient is φ = 180325440.

The previous prime is 666216653. The next prime is 666216721. The reversal of 666216684 is 486612666.

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 31 ways as a sum of consecutive naturals, for example, 8827 + ... + 37554.

Almost surely, 2^666216684 is an apocalyptic number.

It is an amenable number.

666216684 is an abundant number, since it is smaller than the sum of its proper divisors (1411696916).

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

666216684 is a wasteful number, since it uses less digits than its factorization.

666216684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46420 (or 46412 counting only the distinct ones).

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

The square root of 666216684 is about 25811.1736269392. The cubic root of 666216684 is about 873.3838724646.

The spelling of 666216684 in words is "six hundred sixty-six million, two hundred sixteen thousand, six hundred eighty-four".