19998534729 has 12 divisors (see below), whose sum is σ = 27287014128. Its totient is φ = 13021255800.

The previous prime is 19998534727. The next prime is 19998534737. The reversal of 19998534729 is 92743589991.

It is not a de Polignac number, because 19998534729 - 2¹ = 19998534727 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19998534729.

It is not an unprimeable number, because it can be changed into a prime (19998534727) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1599954 + ... + 1612404.

It is an arithmetic number, because the mean of its divisors is an integer number (2273917844).

Almost surely, 2^19998534729 is an apocalyptic number.

It is an amenable number.

19998534729 is a deficient number, since it is larger than the sum of its proper divisors (7288479399).

19998534729 is an frugal number, since it uses more digits than its factorization.

19998534729 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24948 (or 12497 counting only the distinct ones).

The product of its digits is 44089920, while the sum is 66.

The spelling of 19998534729 in words is "nineteen billion, nine hundred ninety-eight million, five hundred thirty-four thousand, seven hundred twenty-nine".