18464388221 has 2 divisors, whose sum is σ = 18464388222. Its totient is φ = 18464388220.

The previous prime is 18464388179. The next prime is 18464388227. The reversal of 18464388221 is 12288346481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17426904121 + 1037484100 = 132011^2 + 32210^2 .

It is a cyclic number.

It is not a de Polignac number, because 18464388221 - 2¹⁸ = 18464126077 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18464388227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9232194110 + 9232194111.

It is an arithmetic number, because the mean of its divisors is an integer number (9232194111).

Almost surely, 2^18464388221 is an apocalyptic number.

It is an amenable number.

18464388221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18464388221 is an equidigital number, since it uses as much as digits as its factorization.

18464388221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 589824, while the sum is 47.

The spelling of 18464388221 in words is "eighteen billion, four hundred sixty-four million, three hundred eighty-eight thousand, two hundred twenty-one".