18921841189 has 2 divisors, whose sum is σ = 18921841190. Its totient is φ = 18921841188.

The previous prime is 18921841151. The next prime is 18921841219. The reversal of 18921841189 is 98114812981.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18448430625 + 473410564 = 135825^2 + 21758^2 .

It is a cyclic number.

It is not a de Polignac number, because 18921841189 - 2⁹ = 18921840677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18921841139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9460920594 + 9460920595.

It is an arithmetic number, because the mean of its divisors is an integer number (9460920595).

Almost surely, 2^18921841189 is an apocalyptic number.

It is an amenable number.

18921841189 is a deficient number, since it is larger than the sum of its proper divisors (1).

18921841189 is an equidigital number, since it uses as much as digits as its factorization.

18921841189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 331776, while the sum is 52.

The spelling of 18921841189 in words is "eighteen billion, nine hundred twenty-one million, eight hundred forty-one thousand, one hundred eighty-nine".