19809888 has 96 divisors (see below), whose sum is σ = 60963840. Its totient is φ = 5514240.

The previous prime is 19809851. The next prime is 19809919. The reversal of 19809888 is 88890891.

It is a tau number, because it is divible by the number of its divisors (96).

It is a self number, because there is not a number n which added to its sum of digits gives 19809888.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27193 + ... + 27911.

It is an arithmetic number, because the mean of its divisors is an integer number (635040).

Almost surely, 2^19809888 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 19809888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30481920).

19809888 is an abundant number, since it is smaller than the sum of its proper divisors (41153952).

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

19809888 is a wasteful number, since it uses less digits than its factorization.

19809888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 780 (or 772 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 51.

The square root of 19809888 is about 4450.8300349485. The cubic root of 19809888 is about 270.5789497388.

The spelling of 19809888 in words is "nineteen million, eight hundred nine thousand, eight hundred eighty-eight".