19991100990 has 256 divisors, whose sum is σ = 60080486400. Its totient is φ = 4153669632.

The previous prime is 19991100979. The next prime is 19991101001. The reversal of 19991100990 is 9900119991.

19991100990 is a nontrivial binomial coefficient, being equal to C(199956, 2).

It is an interprime number because it is at equal distance from previous prime (19991100979) and next prime (19991101001).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 22794432 + ... + 22795308.

It is an arithmetic number, because the mean of its divisors is an integer number (234689400).

Almost surely, 2^19991100990 is an apocalyptic number.

19991100990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

19991100990 is the 199955-th triangular number and also the 99978-th hexagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19991100990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30040243200).

19991100990 is an abundant number, since it is smaller than the sum of its proper divisors (40089385410).

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

19991100990 is a wasteful number, since it uses less digits than its factorization.

19991100990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1139.

The product of its (nonzero) digits is 59049, while the sum is 48.

The spelling of 19991100990 in words is "nineteen billion, nine hundred ninety-one million, one hundred thousand, nine hundred ninety".