18036038221 has 2 divisors, whose sum is σ = 18036038222. Its totient is φ = 18036038220.

The previous prime is 18036038219. The next prime is 18036038233. The reversal of 18036038221 is 12283063081.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9970022500 + 8066015721 = 99850^2 + 89811^2 .

It is a cyclic number.

It is not a de Polignac number, because 18036038221 - 2¹ = 18036038219 is a prime.

Together with 18036038219, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18036038291) 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, 9018019110 + 9018019111.

It is an arithmetic number, because the mean of its divisors is an integer number (9018019111).

Almost surely, 2^18036038221 is an apocalyptic number.

It is an amenable number.

18036038221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18036038221 is an equidigital number, since it uses as much as digits as its factorization.

18036038221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 34.

The spelling of 18036038221 in words is "eighteen billion, thirty-six million, thirty-eight thousand, two hundred twenty-one".