18997935889 has 9 divisors (see below), whose sum is σ = 19101178737. Its totient is φ = 18895250304.

The previous prime is 18997935883. The next prime is 18997935911. The reversal of 18997935889 is 98853979981.

The square root of 18997935889 is 137833.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 1146838225 + 17851097664 = 33865^2 + 133608^2 .

It is not a de Polignac number, because 18997935889 - 2³³ = 10408001297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18997935883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 46449517 + ... + 46449925.

It is an arithmetic number, because the mean of its divisors is an integer number (2122353193).

Almost surely, 2^18997935889 is an apocalyptic number.

18997935889 is the 137833-rd square number.

18997935889 is the 68917-th centered octagonal number.

It is an amenable number.

18997935889 is a deficient number, since it is larger than the sum of its proper divisors (103242848).

18997935889 is an frugal number, since it uses more digits than its factorization.

18997935889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1492 (or 746 counting only the distinct ones).

The product of its digits is 352719360, while the sum is 76.

The spelling of 18997935889 in words is "eighteen billion, nine hundred ninety-seven million, nine hundred thirty-five thousand, eight hundred eighty-nine".