2011391 has 2 divisors, whose sum is σ = 2011392. Its totient is φ = 2011390.

The previous prime is 2011381. The next prime is 2011393. The reversal of 2011391 is 1931102.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2011391 - 2¹⁸ = 1749247 is a prime.

It is a Sophie Germain prime.

Together with 2011393, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2011393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1005695 + 1005696.

It is an arithmetic number, because the mean of its divisors is an integer number (1005696).

2^2011391 is an apocalyptic number.

2011391 is a deficient number, since it is larger than the sum of its proper divisors (1).

2011391 is an equidigital number, since it uses as much as digits as its factorization.

2011391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 54, while the sum is 17.

The square root of 2011391 is about 1418.2351709078. The cubic root of 2011391 is about 126.2308483186.

Adding to 2011391 its reverse (1931102), we get a palindrome (3942493).

It can be divided in two parts, 20 and 11391, that added together give a palindrome (11411).

The spelling of 2011391 in words is "two million, eleven thousand, three hundred ninety-one".