19718507844 has 144 divisors (see below), whose sum is σ = 59505788160. Its totient is φ = 5383065600.

The previous prime is 19718507803. The next prime is 19718507849. The reversal of 19718507844 is 44870581791.

19718507844 is a `hidden beast` number, since 1 + 97 + 1 + 8 + 507 + 8 + 44 = 666.

It is not an unprimeable number, because it can be changed into a prime (19718507849) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 10437652 + ... + 10439540.

It is an arithmetic number, because the mean of its divisors is an integer number (413234640).

Almost surely, 2^19718507844 is an apocalyptic number.

19718507844 is a gapful number since it is divisible by the number (14) 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 19718507844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29752894080).

19718507844 is an abundant number, since it is smaller than the sum of its proper divisors (39787280316).

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

19718507844 is a wasteful number, since it uses less digits than its factorization.

19718507844 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3730 (or 3725 counting only the distinct ones).

The product of its (nonzero) digits is 2257920, while the sum is 54.

The spelling of 19718507844 in words is "nineteen billion, seven hundred eighteen million, five hundred seven thousand, eight hundred forty-four".