18319820509 has 2 divisors, whose sum is σ = 18319820510. Its totient is φ = 18319820508.

The previous prime is 18319820447. The next prime is 18319820537. The reversal of 18319820509 is 90502891381.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18096168484 + 223652025 = 134522^2 + 14955^2 .

It is a cyclic number.

It is not a de Polignac number, because 18319820509 - 2³³ = 9729885917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18319820549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9159910254 + 9159910255.

It is an arithmetic number, because the mean of its divisors is an integer number (9159910255).

Almost surely, 2^18319820509 is an apocalyptic number.

It is an amenable number.

18319820509 is a deficient number, since it is larger than the sum of its proper divisors (1).

18319820509 is an equidigital number, since it uses as much as digits as its factorization.

18319820509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 155520, while the sum is 46.

The spelling of 18319820509 in words is "eighteen billion, three hundred nineteen million, eight hundred twenty thousand, five hundred nine".