11685561 has 8 divisors (see below), whose sum is σ = 15611424. Its totient is φ = 7775040.

The previous prime is 11685523. The next prime is 11685581. The reversal of 11685561 is 16558611.

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

It is not a de Polignac number, because 11685561 - 2⁶ = 11685497 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11685581) 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, 1920 + ... + 5201.

It is an arithmetic number, because the mean of its divisors is an integer number (1951428).

Almost surely, 2^11685561 is an apocalyptic number.

It is an amenable number.

11685561 is a deficient number, since it is larger than the sum of its proper divisors (3925863).

11685561 is an equidigital number, since it uses as much as digits as its factorization.

11685561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7671.

The product of its digits is 7200, while the sum is 33.

The square root of 11685561 is about 3418.4149835852. The cubic root of 11685561 is about 226.9254414327.

It can be divided in two parts, 11685 and 561, that added together give a triangular number (12246 = T₁₅₆).

The spelling of 11685561 in words is "eleven million, six hundred eighty-five thousand, five hundred sixty-one".