18991056050 has 18 divisors (see below), whose sum is σ = 35325176823. Its totient is φ = 7596032640.

The previous prime is 18991055989. The next prime is 18991056053. The reversal of 18991056050 is 5065019981.

It can be written as a sum of positive squares in 5 ways, for example, as 1940449 + 18989115601 = 1393^2 + 137801^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=97445.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18991055992 and 18991056010.

It is not an unprimeable number, because it can be changed into a prime (18991056053) 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 in 8 ways as a sum of consecutive naturals, for example, 964706 + ... + 984194.

Almost surely, 2^18991056050 is an apocalyptic number.

18991056050 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18991056050 is a deficient number, since it is larger than the sum of its proper divisors (16334120773).

18991056050 is an frugal number, since it uses more digits than its factorization.

18991056050 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38990 (or 19496 counting only the distinct ones).

The product of its (nonzero) digits is 97200, while the sum is 44.

The spelling of 18991056050 in words is "eighteen billion, nine hundred ninety-one million, fifty-six thousand, fifty".