18791339909 has 2 divisors, whose sum is σ = 18791339910. Its totient is φ = 18791339908.

The previous prime is 18791339869. The next prime is 18791339953. The reversal of 18791339909 is 90993319781.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10713285025 + 8078054884 = 103505^2 + 89878^2 .

It is a cyclic number.

It is not a de Polignac number, because 18791339909 - 2⁸ = 18791339653 is a prime.

It is a super-2 number, since 2×18791339909² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18791339999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9395669954 + 9395669955.

It is an arithmetic number, because the mean of its divisors is an integer number (9395669955).

Almost surely, 2^18791339909 is an apocalyptic number.

It is an amenable number.

18791339909 is a deficient number, since it is larger than the sum of its proper divisors (1).

18791339909 is an equidigital number, since it uses as much as digits as its factorization.

18791339909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3306744, while the sum is 59.

The spelling of 18791339909 in words is "eighteen billion, seven hundred ninety-one million, three hundred thirty-nine thousand, nine hundred nine".