19726919549 has 2 divisors, whose sum is σ = 19726919550. Its totient is φ = 19726919548.

The previous prime is 19726919521. The next prime is 19726919567. The reversal of 19726919549 is 94591962791.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18938713924 + 788205625 = 137618^2 + 28075^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19726919549 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19726919491 and 19726919500.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19726919599) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9863459774 + 9863459775.

It is an arithmetic number, because the mean of its divisors is an integer number (9863459775).

Almost surely, 2^19726919549 is an apocalyptic number.

It is an amenable number.

19726919549 is a deficient number, since it is larger than the sum of its proper divisors (1).

19726919549 is an equidigital number, since it uses as much as digits as its factorization.

19726919549 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11022480, while the sum is 62.

The spelling of 19726919549 in words is "nineteen billion, seven hundred twenty-six million, nine hundred nineteen thousand, five hundred forty-nine".