11591581 has 2 divisors, whose sum is σ = 11591582. Its totient is φ = 11591580.

The previous prime is 11591557. The next prime is 11591611. The reversal of 11591581 is 18519511.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11088900 + 502681 = 3330^2 + 709^2 .

It is a cyclic number.

It is not a de Polignac number, because 11591581 - 2⁵ = 11591549 is a prime.

It is a super-2 number, since 2×11591581² = 268729500159122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11591681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5795790 + 5795791.

It is an arithmetic number, because the mean of its divisors is an integer number (5795791).

Almost surely, 2^11591581 is an apocalyptic number.

It is an amenable number.

11591581 is a deficient number, since it is larger than the sum of its proper divisors (1).

11591581 is an equidigital number, since it uses as much as digits as its factorization.

11591581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1800, while the sum is 31.

The square root of 11591581 is about 3404.6410970909. The cubic root of 11591581 is about 226.3154612531.

The spelling of 11591581 in words is "eleven million, five hundred ninety-one thousand, five hundred eighty-one".