19999891080 has 96 divisors (see below), whose sum is σ = 69999635160. Its totient is φ = 4923048960.

The previous prime is 19999891057. The next prime is 19999891081. The reversal of 19999891080 is 8019899991.

It can be written as a sum of positive squares in 4 ways, for example, as 6730233444 + 13269657636 = 82038^2 + 115194^2 .

It is a junction number, because it is equal to n+sod(n) for n = 19999890999 and 19999891017.

It is not an unprimeable number, because it can be changed into a prime (19999891081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2132061 + ... + 2141420.

Almost surely, 2^19999891080 is an apocalyptic number.

19999891080 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

19999891080 is an abundant number, since it is smaller than the sum of its proper divisors (49999744080).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19999891080 is a wasteful number, since it uses less digits than its factorization.

19999891080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4273511 (or 4273504 counting only the distinct ones).

The product of its (nonzero) digits is 3779136, while the sum is 63.

The spelling of 19999891080 in words is "nineteen billion, nine hundred ninety-nine million, eight hundred ninety-one thousand, eighty".