19809558328849 has 9 divisors (see below), whose sum is σ = 19937240803857. Its totient is φ = 19682688474384.

The previous prime is 19809558328793. The next prime is 19809558328883. The reversal of 19809558328849 is 94882385590891.

The square root of 19809558328849 is 4450793.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 10297071299025 + 9512487029824 = 3208905^2 + 3084232^2 .

It is not a de Polignac number, because 19809558328849 - 2¹¹ = 19809558326801 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19809558928849) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 698760327 + ... + 698788675.

Almost surely, 2^{19809558328849} is an apocalyptic number.

19809558328849 is the 4450793-rd square number.

19809558328849 is the 2225397-th centered octagonal number.

It is an amenable number.

19809558328849 is a deficient number, since it is larger than the sum of its proper divisors (127682475008).

19809558328849 is an frugal number, since it uses more digits than its factorization.

19809558328849 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57012 (or 28506 counting only the distinct ones).

The product of its (nonzero) digits is 1791590400, while the sum is 79.

The spelling of 19809558328849 in words is "nineteen trillion, eight hundred nine billion, five hundred fifty-eight million, three hundred twenty-eight thousand, eight hundred forty-nine".