1991095 has 4 divisors (see below), whose sum is σ = 2389320. Its totient is φ = 1592872.

The previous prime is 1991089. The next prime is 1991107. The reversal of 1991095 is 5901991.

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 1991095 - 2⁵ = 1991063 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1991095.

It is a congruent number.

It is an unprimeable number.

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, 199105 + ... + 199114.

It is an arithmetic number, because the mean of its divisors is an integer number (597330).

2^1991095 is an apocalyptic number.

1991095 is a deficient number, since it is larger than the sum of its proper divisors (398225).

1991095 is an equidigital number, since it uses as much as digits as its factorization.

1991095 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 398224.

The product of its (nonzero) digits is 3645, while the sum is 34.

The square root of 1991095 is about 1411.0616570512. The cubic root of 1991095 is about 125.8048334893.

The spelling of 1991095 in words is "one million, nine hundred ninety-one thousand, ninety-five".