19549680509 has 2 divisors, whose sum is σ = 19549680510. Its totient is φ = 19549680508.

The previous prime is 19549680439. The next prime is 19549680511. The reversal of 19549680509 is 90508694591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19431523609 + 118156900 = 139397^2 + 10870^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19549680509 is a prime.

Together with 19549680511, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19549680589) 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, 9774840254 + 9774840255.

It is an arithmetic number, because the mean of its divisors is an integer number (9774840255).

Almost surely, 2^19549680509 is an apocalyptic number.

It is an amenable number.

19549680509 is a deficient number, since it is larger than the sum of its proper divisors (1).

19549680509 is an equidigital number, since it uses as much as digits as its factorization.

19549680509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3499200, while the sum is 56.

The spelling of 19549680509 in words is "nineteen billion, five hundred forty-nine million, six hundred eighty thousand, five hundred nine".