19857813888 has 128 divisors (see below), whose sum is σ = 57784256640. Its totient is φ = 5992243200.

The previous prime is 19857813869. The next prime is 19857813889. The reversal of 19857813888 is 88831875891.

It is a tau number, because it is divible by the number of its divisors (128).

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19857813889) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1008231 + ... + 1027737.

It is an arithmetic number, because the mean of its divisors is an integer number (451439505).

Almost surely, 2^19857813888 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 19857813888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28892128320).

19857813888 is an abundant number, since it is smaller than the sum of its proper divisors (37926442752).

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

19857813888 is a wasteful number, since it uses less digits than its factorization.

19857813888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19776 (or 19764 counting only the distinct ones).

The product of its digits is 30965760, while the sum is 66.

The spelling of 19857813888 in words is "nineteen billion, eight hundred fifty-seven million, eight hundred thirteen thousand, eight hundred eighty-eight".