128331389 has 4 divisors (see below), whose sum is σ = 128385756. Its totient is φ = 128277024.

The previous prime is 128331383. The next prime is 128331403. The reversal of 128331389 is 983133821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 983133821 = 1987 ⋅494783.

It can be written as a sum of positive squares in 2 ways, for example, as 48372025 + 79959364 = 6955^2 + 8942^2 .

It is a cyclic number.

It is not a de Polignac number, because 128331389 - 2²⁴ = 111554173 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 (128331383) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23474 + ... + 28419.

It is an arithmetic number, because the mean of its divisors is an integer number (32096439).

Almost surely, 2^128331389 is an apocalyptic number.

It is an amenable number.

128331389 is a deficient number, since it is larger than the sum of its proper divisors (54367).

128331389 is an equidigital number, since it uses as much as digits as its factorization.

128331389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54366.

The product of its digits is 31104, while the sum is 38.

The square root of 128331389 is about 11328.3444951149. The cubic root of 128331389 is about 504.4029659728.

The spelling of 128331389 in words is "one hundred twenty-eight million, three hundred thirty-one thousand, three hundred eighty-nine".