18668840213 has 4 divisors (see below), whose sum is σ = 19173403500. Its totient is φ = 18164276928.

The previous prime is 18668840209. The next prime is 18668840227. The reversal of 18668840213 is 31204886681.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 11842445329 + 6826394884 = 108823^2 + 82622^2 .

It is a cyclic number.

It is not a de Polignac number, because 18668840213 - 2² = 18668840209 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18668840273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 252281588 + ... + 252281661.

It is an arithmetic number, because the mean of its divisors is an integer number (4793350875).

Almost surely, 2^18668840213 is an apocalyptic number.

It is an amenable number.

18668840213 is a deficient number, since it is larger than the sum of its proper divisors (504563287).

18668840213 is an equidigital number, since it uses as much as digits as its factorization.

18668840213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 504563286.

The product of its (nonzero) digits is 442368, while the sum is 47.

The spelling of 18668840213 in words is "eighteen billion, six hundred sixty-eight million, eight hundred forty thousand, two hundred thirteen".