19998565544 has 16 divisors (see below), whose sum is σ = 37521081600. Its totient is φ = 9992943792.

The previous prime is 19998565529. The next prime is 19998565549. The reversal of 19998565544 is 44556589991.

It is not an unprimeable number, because it can be changed into a prime (19998565549) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 778952 + ... + 804215.

It is an arithmetic number, because the mean of its divisors is an integer number (2345067600).

Almost surely, 2^19998565544 is an apocalyptic number.

It is an amenable number.

19998565544 is a deficient number, since it is larger than the sum of its proper divisors (17522516056).

19998565544 is a wasteful number, since it uses less digits than its factorization.

19998565544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1584752 (or 1584748 counting only the distinct ones).

The product of its digits is 69984000, while the sum is 65.

The spelling of 19998565544 in words is "nineteen billion, nine hundred ninety-eight million, five hundred sixty-five thousand, five hundred forty-four".