18170928221 has 2 divisors, whose sum is σ = 18170928222. Its totient is φ = 18170928220.

The previous prime is 18170928197. The next prime is 18170928233. The reversal of 18170928221 is 12282907181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13697191225 + 4473736996 = 117035^2 + 66886^2 .

It is a cyclic number.

It is not a de Polignac number, because 18170928221 - 2⁶ = 18170928157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18170928271) 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, 9085464110 + 9085464111.

It is an arithmetic number, because the mean of its divisors is an integer number (9085464111).

Almost surely, 2^18170928221 is an apocalyptic number.

It is an amenable number.

18170928221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18170928221 is an equidigital number, since it uses as much as digits as its factorization.

18170928221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 41.

The spelling of 18170928221 in words is "eighteen billion, one hundred seventy million, nine hundred twenty-eight thousand, two hundred twenty-one".