18917414221 has 2 divisors, whose sum is σ = 18917414222. Its totient is φ = 18917414220.

The previous prime is 18917414213. The next prime is 18917414267. The reversal of 18917414221 is 12241471981.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17794226025 + 1123188196 = 133395^2 + 33514^2 .

It is a cyclic number.

It is not a de Polignac number, because 18917414221 - 2³ = 18917414213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18917414291) 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, 9458707110 + 9458707111.

It is an arithmetic number, because the mean of its divisors is an integer number (9458707111).

Almost surely, 2^18917414221 is an apocalyptic number.

It is an amenable number.

18917414221 is a deficient number, since it is larger than the sum of its proper divisors (1).

18917414221 is an equidigital number, since it uses as much as digits as its factorization.

18917414221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 32256, while the sum is 40.

The spelling of 18917414221 in words is "eighteen billion, nine hundred seventeen million, four hundred fourteen thousand, two hundred twenty-one".