11561591 has 2 divisors, whose sum is σ = 11561592. Its totient is φ = 11561590.

The previous prime is 11561531. The next prime is 11561629. The reversal of 11561591 is 19516511.

11561591 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 11561591 - 2²² = 7367287 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11561531) 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 as a sum of consecutive naturals, namely, 5780795 + 5780796.

It is an arithmetic number, because the mean of its divisors is an integer number (5780796).

Almost surely, 2^11561591 is an apocalyptic number.

11561591 is a deficient number, since it is larger than the sum of its proper divisors (1).

11561591 is an equidigital number, since it uses as much as digits as its factorization.

11561591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1350, while the sum is 29.

The square root of 11561591 is about 3400.2339625385. The cubic root of 11561591 is about 226.1201165328.

The spelling of 11561591 in words is "eleven million, five hundred sixty-one thousand, five hundred ninety-one".