19894649891 has 24 divisors (see below), whose sum is σ = 21709369920. Its totient is φ = 18221208192.

The previous prime is 19894649867. The next prime is 19894649939.

19894649891 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 19894649891 - 2²² = 19890455587 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19894649821) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1600940 + ... + 1613318.

It is an arithmetic number, because the mean of its divisors is an integer number (904557080).

Almost surely, 2^19894649891 is an apocalyptic number.

19894649891 is a deficient number, since it is larger than the sum of its proper divisors (1814720029).

19894649891 is a wasteful number, since it uses less digits than its factorization.

19894649891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12563 (or 12546 counting only the distinct ones).

The product of its digits is 40310784, while the sum is 68.

The spelling of 19894649891 in words is "nineteen billion, eight hundred ninety-four million, six hundred forty-nine thousand, eight hundred ninety-one".