1311891 has 16 divisors (see below), whose sum is σ = 2016000. Its totient is φ = 743328.

The previous prime is 1311857. The next prime is 1311899. The reversal of 1311891 is 1981131.

It is not a de Polignac number, because 1311891 - 2¹⁵ = 1279123 is a prime.

1311891 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (1311899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3585 + ... + 3933.

It is an arithmetic number, because the mean of its divisors is an integer number (126000).

2^1311891 is an apocalyptic number.

1311891 is a deficient number, since it is larger than the sum of its proper divisors (704109).

1311891 is a wasteful number, since it uses less digits than its factorization.

1311891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 538.

The product of its digits is 216, while the sum is 24.

The square root of 1311891 is about 1145.3781035099. The cubic root of 1311891 is about 109.4710417367.

The spelling of 1311891 in words is "one million, three hundred eleven thousand, eight hundred ninety-one".