1091083891 has 4 divisors (see below), whose sum is σ = 1092906000. Its totient is φ = 1089261784.

The previous prime is 1091083853. The next prime is 1091083921. The reversal of 1091083891 is 1983801901.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1983801901 = 89 ⋅22289909.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1091083891 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1091083831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 910156 + ... + 911353.

It is an arithmetic number, because the mean of its divisors is an integer number (273226500).

Almost surely, 2^1091083891 is an apocalyptic number.

1091083891 is a deficient number, since it is larger than the sum of its proper divisors (1822109).

1091083891 is an equidigital number, since it uses as much as digits as its factorization.

1091083891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1822108.

The product of its (nonzero) digits is 15552, while the sum is 40.

The square root of 1091083891 is about 33031.5590155839. The cubic root of 1091083891 is about 1029.4834784122.

The spelling of 1091083891 in words is "one billion, ninety-one million, eighty-three thousand, eight hundred ninety-one".