1328905091 has 4 divisors (see below), whose sum is σ = 1334708400. Its totient is φ = 1323101784.

The previous prime is 1328905043. The next prime is 1328905111. The reversal of 1328905091 is 1905098231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1905098231 = 4057 ⋅469583.

It is a cyclic number.

It is not a de Polignac number, because 1328905091 - 2⁶ = 1328905027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1328905021) 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, 2901311 + ... + 2901768.

It is an arithmetic number, because the mean of its divisors is an integer number (333677100).

Almost surely, 2^1328905091 is an apocalyptic number.

1328905091 is a deficient number, since it is larger than the sum of its proper divisors (5803309).

1328905091 is an equidigital number, since it uses as much as digits as its factorization.

1328905091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5803308.

The product of its (nonzero) digits is 19440, while the sum is 38.

The square root of 1328905091 is about 36454.1505318667. The cubic root of 1328905091 is about 1099.4225870396.

The spelling of 1328905091 in words is "one billion, three hundred twenty-eight million, nine hundred five thousand, ninety-one".