19911090000 has 200 divisors, whose sum is σ = 64567831680. Its totient is φ = 5285504000.

The previous prime is 19911089999. The next prime is 19911090007. The reversal of 19911090000 is 9011991.

It is a tau number, because it is divible by the number of its divisors (200).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a self number, because there is not a number n which added to its sum of digits gives 19911090000.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19911090007) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 7168612 + ... + 7171388.

Almost surely, 2^19911090000 is an apocalyptic number.

19911090000 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19911090000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32283915840).

19911090000 is an abundant number, since it is smaller than the sum of its proper divisors (44656741680).

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

19911090000 is a wasteful number, since it uses less digits than its factorization.

19911090000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3047 (or 3026 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 30.

The spelling of 19911090000 in words is "nineteen billion, nine hundred eleven million, ninety thousand".