11557561 has 4 divisors (see below), whose sum is σ = 11572624. Its totient is φ = 11542500.

The previous prime is 11557549. The next prime is 11557571. The reversal of 11557561 is 16575511.

11557561 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 a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11557561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11557541) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6315 + ... + 7936.

It is an arithmetic number, because the mean of its divisors is an integer number (2893156).

Almost surely, 2^11557561 is an apocalyptic number.

It is an amenable number.

11557561 is a deficient number, since it is larger than the sum of its proper divisors (15063).

11557561 is an equidigital number, since it uses as much as digits as its factorization.

11557561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15062.

The product of its digits is 5250, while the sum is 31.

The square root of 11557561 is about 3399.6413046085. The cubic root of 11557561 is about 226.0938407383.

The spelling of 11557561 in words is "eleven million, five hundred fifty-seven thousand, five hundred sixty-one".