213660666 has 24 divisors (see below), whose sum is σ = 480078144. Its totient is φ = 71220060.

The previous prime is 213660659. The next prime is 213660673. The reversal of 213660666 is 666066312.

It is an interprime number because it is at equal distance from previous prime (213660659) and next prime (213660673).

It is a self number, because there is not a number n which added to its sum of digits gives 213660666.

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, 219330 + ... + 220301.

It is an arithmetic number, because the mean of its divisors is an integer number (20003256).

Almost surely, 2^213660666 is an apocalyptic number.

213660666 is an abundant number, since it is smaller than the sum of its proper divisors (266417478).

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

213660666 is an equidigital number, since it uses as much as digits as its factorization.

213660666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 439648 (or 439636 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 213660666 is about 14617.1360395941. The cubic root of 213660666 is about 597.8260829874.

The spelling of 213660666 in words is "two hundred thirteen million, six hundred sixty thousand, six hundred sixty-six".