19806111808 has 112 divisors (see below), whose sum is σ = 46986992640. Its totient is φ = 8099080704.

The previous prime is 19806111797. The next prime is 19806111881. The reversal of 19806111808 is 80811160891.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (112).

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 4562503 + ... + 4566841.

It is an arithmetic number, because the mean of its divisors is an integer number (419526720).

Almost surely, 2^19806111808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19806111808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23493496320).

19806111808 is an abundant number, since it is smaller than the sum of its proper divisors (27180880832).

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

19806111808 is a wasteful number, since it uses less digits than its factorization.

19806111808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4824 (or 4814 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 43.

The spelling of 19806111808 in words is "nineteen billion, eight hundred six million, one hundred eleven thousand, eight hundred eight".