18266670387221 has 4 divisors (see below), whose sum is σ = 18266698361100. Its totient is φ = 18266642413344.

The previous prime is 18266670387193. The next prime is 18266670387247. The reversal of 18266670387221 is 12278307666281.

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 1623419998225 + 16643250388996 = 1274135^2 + 4079614^2 .

It is a cyclic number.

It is not a de Polignac number, because 18266670387221 - 2⁶ = 18266670387157 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18266670387281) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 12983456 + ... + 14321433.

It is an arithmetic number, because the mean of its divisors is an integer number (4566674590275).

Almost surely, 2^{18266670387221} is an apocalyptic number.

It is an amenable number.

18266670387221 is a deficient number, since it is larger than the sum of its proper divisors (27973879).

18266670387221 is an equidigital number, since it uses as much as digits as its factorization.

18266670387221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27973878.

The product of its (nonzero) digits is 16257024, while the sum is 59.

The spelling of 18266670387221 in words is "eighteen trillion, two hundred sixty-six billion, six hundred seventy million, three hundred eighty-seven thousand, two hundred twenty-one".