19985663544 has 256 divisors, whose sum is σ = 64718438400. Its totient is φ = 4991155200.

The previous prime is 19985663521. The next prime is 19985663561. The reversal of 19985663544 is 44536658991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9566052 + ... + 9568140.

It is an arithmetic number, because the mean of its divisors is an integer number (252806400).

Almost surely, 2^19985663544 is an apocalyptic number.

19985663544 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 19985663544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32359219200).

19985663544 is an abundant number, since it is smaller than the sum of its proper divisors (44732774856).

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

19985663544 is a wasteful number, since it uses less digits than its factorization.

19985663544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2314 (or 2310 counting only the distinct ones).

The product of its digits is 27993600, while the sum is 60.

The spelling of 19985663544 in words is "nineteen billion, nine hundred eighty-five million, six hundred sixty-three thousand, five hundred forty-four".