165988611889 has 27 divisors (see below), whose sum is σ = 179905654539. Its totient is φ = 153123605280.

The previous prime is 165988611869. The next prime is 165988611917. The reversal of 165988611889 is 988116889561.

The square root of 165988611889 is 407417.

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

165988611889 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 7998261489 + 157990350400 = 89433^2 + 397480^2 .

It is not a de Polignac number, because 165988611889 - 2⁵ = 165988611857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165988611839) 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 26 ways as a sum of consecutive naturals, for example, 317377582 + ... + 317378104.

Almost surely, 2^165988611889 is an apocalyptic number.

165988611889 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

165988611889 is the 407417-th square number.

165988611889 is the 203709-th centered octagonal number.

It is an amenable number.

165988611889 is a deficient number, since it is larger than the sum of its proper divisors (13917042650).

165988611889 is an frugal number, since it uses more digits than its factorization.

165988611889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1166 (or 583 counting only the distinct ones).

The product of its digits is 59719680, while the sum is 70.

The spelling of 165988611889 in words is "one hundred sixty-five billion, nine hundred eighty-eight million, six hundred eleven thousand, eight hundred eighty-nine".