3091991 has 4 divisors (see below), whose sum is σ = 3533712. Its totient is φ = 2650272.

The previous prime is 3091987. The next prime is 3091997. The reversal of 3091991 is 1991903.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 3091991 - 2² = 3091987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3091997) 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, 220850 + ... + 220863.

It is an arithmetic number, because the mean of its divisors is an integer number (883428).

Almost surely, 2^3091991 is an apocalyptic number.

3091991 is a deficient number, since it is larger than the sum of its proper divisors (441721).

3091991 is an equidigital number, since it uses as much as digits as its factorization.

3091991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441720.

The product of its (nonzero) digits is 2187, while the sum is 32.

The square root of 3091991 is about 1758.4058120923. The cubic root of 3091991 is about 145.6842962486.

The spelling of 3091991 in words is "three million, ninety-one thousand, nine hundred ninety-one".