1991411 has 4 divisors (see below), whose sum is σ = 2040024. Its totient is φ = 1942800.

The previous prime is 1991389. The next prime is 1991413. The reversal of 1991411 is 1141991.

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 1991411 - 2¹⁴ = 1975027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1991413) 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, 24245 + ... + 24326.

It is an arithmetic number, because the mean of its divisors is an integer number (510006).

2^1991411 is an apocalyptic number.

1991411 is a deficient number, since it is larger than the sum of its proper divisors (48613).

1991411 is an equidigital number, since it uses as much as digits as its factorization.

1991411 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 48612.

The product of its digits is 324, while the sum is 26.

The square root of 1991411 is about 1411.1736250370. The cubic root of 1991411 is about 125.8114884914.

The spelling of 1991411 in words is "one million, nine hundred ninety-one thousand, four hundred eleven".