8189128821 has 4 divisors (see below), whose sum is σ = 10918838432. Its totient is φ = 5459419212.

The previous prime is 8189128813. The next prime is 8189128823. The reversal of 8189128821 is 1288219818.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 8189128821 - 2³ = 8189128813 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8189128823) 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, 1364854801 + ... + 1364854806.

It is an arithmetic number, because the mean of its divisors is an integer number (2729709608).

Almost surely, 2^8189128821 is an apocalyptic number.

It is an amenable number.

8189128821 is a deficient number, since it is larger than the sum of its proper divisors (2729709611).

8189128821 is a wasteful number, since it uses less digits than its factorization.

8189128821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2729709610.

The product of its digits is 147456, while the sum is 48.

The square root of 8189128821 is about 90493.8054288800. The cubic root of 8189128821 is about 2015.6381406674.

The spelling of 8189128821 in words is "eight billion, one hundred eighty-nine million, one hundred twenty-eight thousand, eight hundred twenty-one".