18435549221 has 2 divisors, whose sum is σ = 18435549222. Its totient is φ = 18435549220.

The previous prime is 18435549193. The next prime is 18435549239. The reversal of 18435549221 is 12294553481.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12763350625 + 5672198596 = 112975^2 + 75314^2 .

It is a cyclic number.

It is not a de Polignac number, because 18435549221 - 2¹⁸ = 18435287077 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18435549281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9217774610 + 9217774611.

It is an arithmetic number, because the mean of its divisors is an integer number (9217774611).

Almost surely, 2^18435549221 is an apocalyptic number.

It is an amenable number.

18435549221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18435549221 is an equidigital number, since it uses as much as digits as its factorization.

18435549221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 345600, while the sum is 44.

The spelling of 18435549221 in words is "eighteen billion, four hundred thirty-five million, five hundred forty-nine thousand, two hundred twenty-one".