18965972089 has 9 divisors (see below), whose sum is σ = 20149731021. Its totient is φ = 17848123200.

The previous prime is 18965972071. The next prime is 18965972099. The reversal of 18965972089 is 98027956981.

The square root of 18965972089 is 137717.

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 14410802025 + 4555170064 = 120045^2 + 67492^2 .

It is not a de Polignac number, because 18965972089 - 2⁷ = 18965971961 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18965972089.

It is not an unprimeable number, because it can be changed into a prime (18965972009) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2337139 + ... + 2345239.

Almost surely, 2^18965972089 is an apocalyptic number.

18965972089 is the 137717-th square number.

18965972089 is the 68859-th centered octagonal number.

It is an amenable number.

18965972089 is a deficient number, since it is larger than the sum of its proper divisors (1183758932).

18965972089 is an frugal number, since it uses more digits than its factorization.

18965972089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16236 (or 8118 counting only the distinct ones).

The product of its (nonzero) digits is 19595520, while the sum is 64.

Multiplying 18965972089 by its sum of digits (64), we get a square (1213822213696 = 1101736²).

The spelling of 18965972089 in words is "eighteen billion, nine hundred sixty-five million, nine hundred seventy-two thousand, eighty-nine".