19999900000 has 72 divisors (see below), whose sum is σ = 49215600000. Its totient is φ = 7999920000.

The previous prime is 19999899919. The next prime is 19999900007. The reversal of 19999900000 is 999991.

19999900000 is a nontrivial binomial coefficient, being equal to C(200000, 2).

19999900000 is an astonishing number since 19999900000 = 0 + ... + 199999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19999900007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1 + ... + 199999.

It is an arithmetic number, because the mean of its divisors is an integer number (683550000).

Almost surely, 2^19999900000 is an apocalyptic number.

19999900000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19999900000 is the 199999-th triangular number and also the 100000-th hexagonal number.

19999900000 is the 66667-th centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19999900000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24607800000).

19999900000 is an abundant number, since it is smaller than the sum of its proper divisors (29215700000).

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

19999900000 is an frugal number, since it uses more digits than its factorization.

19999900000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200034 (or 200006 counting only the distinct ones).

The product of its (nonzero) digits is 59049, while the sum is 46.

The spelling of 19999900000 in words is "nineteen billion, nine hundred ninety-nine million, nine hundred thousand".