11561566 has 4 divisors (see below), whose sum is σ = 17342352. Its totient is φ = 5780782.

The previous prime is 11561531. The next prime is 11561591. The reversal of 11561566 is 66516511.

11561566 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66516511 = 19 ⋅3500869.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2890390 + ... + 2890393.

It is an arithmetic number, because the mean of its divisors is an integer number (4335588).

Almost surely, 2^11561566 is an apocalyptic number.

11561566 is a deficient number, since it is larger than the sum of its proper divisors (5780786).

11561566 is an equidigital number, since it uses as much as digits as its factorization.

11561566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5780785.

The product of its digits is 5400, while the sum is 31.

The square root of 11561566 is about 3400.2302863189. The cubic root of 11561566 is about 226.1199535505.

The spelling of 11561566 in words is "eleven million, five hundred sixty-one thousand, five hundred sixty-six".