1000191091 has 4 divisors (see below), whose sum is σ = 1000271800. Its totient is φ = 1000110384.

The previous prime is 1000191089. The next prime is 1000191097. The reversal of 1000191091 is 1901910001.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1901910001 = 37 ⋅51402973.

It is a cyclic number.

It is not a de Polignac number, because 1000191091 - 2¹ = 1000191089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1000191097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17421 + ... + 47998.

It is an arithmetic number, because the mean of its divisors is an integer number (250067950).

Almost surely, 2^1000191091 is an apocalyptic number.

1000191091 is a deficient number, since it is larger than the sum of its proper divisors (80709).

1000191091 is an equidigital number, since it uses as much as digits as its factorization.

1000191091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80708.

The product of its (nonzero) digits is 81, while the sum is 22.

The square root of 1000191091 is about 31625.7978713581. The cubic root of 1000191091 is about 1000.0636929431.

The spelling of 1000191091 in words is "one billion, one hundred ninety-one thousand, ninety-one".