19888891 has 6 divisors (see below), whose sum is σ = 21861476. Its totient is φ = 18080700.

The previous prime is 19888889. The next prime is 19888901.

19888891 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 19888891 - 2¹ = 19888889 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19888811) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 82065 + ... + 82306.

Almost surely, 2^19888891 is an apocalyptic number.

19888891 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

19888891 is a deficient number, since it is larger than the sum of its proper divisors (1972585).

19888891 is a wasteful number, since it uses less digits than its factorization.

19888891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164393 (or 164382 counting only the distinct ones).

The product of its digits is 331776, while the sum is 52.

The square root of 19888891 is about 4459.6962901077. The cubic root of 19888891 is about 270.9381675628.

The spelling of 19888891 in words is "nineteen million, eight hundred eighty-eight thousand, eight hundred ninety-one".