11591561 has 8 divisors (see below), whose sum is σ = 12285000. Its totient is φ = 10917760.

The previous prime is 11591557. The next prime is 11591581. The reversal of 11591561 is 16519511.

It can be written as a sum of positive squares in 4 ways, for example, as 65536 + 11526025 = 256^2 + 3395^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 11591561 - 2² = 11591557 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11591581) 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 7 ways as a sum of consecutive naturals, for example, 3686 + ... + 6063.

It is an arithmetic number, because the mean of its divisors is an integer number (1535625).

Almost surely, 2^11591561 is an apocalyptic number.

It is an amenable number.

11591561 is a deficient number, since it is larger than the sum of its proper divisors (693439).

11591561 is an equidigital number, since it uses as much as digits as its factorization.

11591561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9819.

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

The square root of 11591561 is about 3404.6381599224. The cubic root of 11591561 is about 226.3153310922.

The spelling of 11591561 in words is "eleven million, five hundred ninety-one thousand, five hundred sixty-one".