8128443809 has 4 divisors (see below), whose sum is σ = 8151470916. Its totient is φ = 8105416704.

The previous prime is 8128443793. The next prime is 8128443839. The reversal of 8128443809 is 9083448218.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1251390625 + 6877053184 = 35375^2 + 82928^2 .

It is a cyclic number.

It is not a de Polignac number, because 8128443809 - 2⁴ = 8128443793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (8128443839) 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, 11513024 + ... + 11513729.

It is an arithmetic number, because the mean of its divisors is an integer number (2037867729).

Almost surely, 2^8128443809 is an apocalyptic number.

It is an amenable number.

8128443809 is a deficient number, since it is larger than the sum of its proper divisors (23027107).

8128443809 is a wasteful number, since it uses less digits than its factorization.

8128443809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23027106.

The product of its (nonzero) digits is 442368, while the sum is 47.

The square root of 8128443809 is about 90157.8826781108. The cubic root of 8128443809 is about 2010.6468722320.

The spelling of 8128443809 in words is "eight billion, one hundred twenty-eight million, four hundred forty-three thousand, eight hundred nine".