18512259221 has 2 divisors, whose sum is σ = 18512259222. Its totient is φ = 18512259220.

The previous prime is 18512259217. The next prime is 18512259307. The reversal of 18512259221 is 12295221581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9958044100 + 8554215121 = 99790^2 + 92489^2 .

It is a cyclic number.

It is not a de Polignac number, because 18512259221 - 2² = 18512259217 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18512259121) 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 as a sum of consecutive naturals, namely, 9256129610 + 9256129611.

It is an arithmetic number, because the mean of its divisors is an integer number (9256129611).

Almost surely, 2^18512259221 is an apocalyptic number.

It is an amenable number.

18512259221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18512259221 is an equidigital number, since it uses as much as digits as its factorization.

18512259221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 28800, while the sum is 38.

The spelling of 18512259221 in words is "eighteen billion, five hundred twelve million, two hundred fifty-nine thousand, two hundred twenty-one".