18810421789 has 2 divisors, whose sum is σ = 18810421790. Its totient is φ = 18810421788.

The previous prime is 18810421711. The next prime is 18810421829. The reversal of 18810421789 is 98712401881.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11571304900 + 7239116889 = 107570^2 + 85083^2 .

It is an emirp because it is prime and its reverse (98712401881) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18810421789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18810421589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9405210894 + 9405210895.

It is an arithmetic number, because the mean of its divisors is an integer number (9405210895).

Almost surely, 2^18810421789 is an apocalyptic number.

It is an amenable number.

18810421789 is a deficient number, since it is larger than the sum of its proper divisors (1).

18810421789 is an equidigital number, since it uses as much as digits as its factorization.

18810421789 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 258048, while the sum is 49.

The spelling of 18810421789 in words is "eighteen billion, eight hundred ten million, four hundred twenty-one thousand, seven hundred eighty-nine".