19543642009 has 2 divisors, whose sum is σ = 19543642010. Its totient is φ = 19543642008.

The previous prime is 19543641959. The next prime is 19543642033. The reversal of 19543642009 is 90024634591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10511990784 + 9031651225 = 102528^2 + 95035^2 .

It is an emirp because it is prime and its reverse (90024634591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19543642009 - 2²⁵ = 19510087577 is a prime.

It is not a weakly prime, because it can be changed into another prime (19543646009) 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, 9771821004 + 9771821005.

It is an arithmetic number, because the mean of its divisors is an integer number (9771821005).

Almost surely, 2^19543642009 is an apocalyptic number.

It is an amenable number.

19543642009 is a deficient number, since it is larger than the sum of its proper divisors (1).

19543642009 is an equidigital number, since it uses as much as digits as its factorization.

19543642009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 233280, while the sum is 43.

The spelling of 19543642009 in words is "nineteen billion, five hundred forty-three million, six hundred forty-two thousand, nine".