128330891 has 4 divisors (see below), whose sum is σ = 138202512. Its totient is φ = 118459272.

The previous prime is 128330863. The next prime is 128330897. The reversal of 128330891 is 198033821.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 198033821 = 12473 ⋅15877.

It is a cyclic number.

It is not a de Polignac number, because 128330891 - 2¹⁰ = 128329867 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128330897) 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, 4935791 + ... + 4935816.

It is an arithmetic number, because the mean of its divisors is an integer number (34550628).

Almost surely, 2^128330891 is an apocalyptic number.

128330891 is a deficient number, since it is larger than the sum of its proper divisors (9871621).

128330891 is an equidigital number, since it uses as much as digits as its factorization.

128330891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9871620.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 128330891 is about 11328.3225148298. The cubic root of 128330891 is about 504.4023135135.

The spelling of 128330891 in words is "one hundred twenty-eight million, three hundred thirty thousand, eight hundred ninety-one".