128392817 has 4 divisors (see below), whose sum is σ = 146734656. Its totient is φ = 110050980.

The previous prime is 128392813. The next prime is 128392819. The reversal of 128392817 is 718293821.

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 a cyclic number.

It is not a de Polignac number, because 128392817 - 2² = 128392813 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128392811) 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, 9170909 + ... + 9170922.

It is an arithmetic number, because the mean of its divisors is an integer number (36683664).

Almost surely, 2^128392817 is an apocalyptic number.

It is an amenable number.

128392817 is a deficient number, since it is larger than the sum of its proper divisors (18341839).

128392817 is an equidigital number, since it uses as much as digits as its factorization.

128392817 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18341838.

The product of its digits is 48384, while the sum is 41.

The square root of 128392817 is about 11331.0554230398. The cubic root of 128392817 is about 504.4834334853.

The spelling of 128392817 in words is "one hundred twenty-eight million, three hundred ninety-two thousand, eight hundred seventeen".