19889426688891 has 16 divisors (see below), whose sum is σ = 27083729147904. Its totient is φ = 12977376313664.

The previous prime is 19889426688883. The next prime is 19889426688919. The reversal of 19889426688891 is 19888662498891.

It is a cyclic number.

It is not a de Polignac number, because 19889426688891 - 2³ = 19889426688883 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 19889426688798 and 19889426688807.

It is not an unprimeable number, because it can be changed into a prime (19889426687891) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 15848431 + ... + 17057303.

It is an arithmetic number, because the mean of its divisors is an integer number (1692733071744).

Almost surely, 2^{19889426688891} is an apocalyptic number.

19889426688891 is a deficient number, since it is larger than the sum of its proper divisors (7194302459013).

19889426688891 is a wasteful number, since it uses less digits than its factorization.

19889426688891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1325610.

The product of its digits is 6879707136, while the sum is 87.

The spelling of 19889426688891 in words is "nineteen trillion, eight hundred eighty-nine billion, four hundred twenty-six million, six hundred eighty-eight thousand, eight hundred ninety-one".