11715561 has 24 divisors (see below), whose sum is σ = 19883136. Its totient is φ = 6553440.

The previous prime is 11715527. The next prime is 11715577. The reversal of 11715561 is 16551711.

It is a happy number.

It is not a de Polignac number, because 11715561 - 2⁷ = 11715433 is a prime.

It is not an unprimeable number, because it can be changed into a prime (11715511) 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 23 ways as a sum of consecutive naturals, for example, 3265 + ... + 5838.

It is an arithmetic number, because the mean of its divisors is an integer number (828464).

Almost surely, 2^11715561 is an apocalyptic number.

11715561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

11715561 is a deficient number, since it is larger than the sum of its proper divisors (8167575).

11715561 is a wasteful number, since it uses less digits than its factorization.

11715561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9133 (or 9130 counting only the distinct ones).

The product of its digits is 1050, while the sum is 27.

The square root of 11715561 is about 3422.8001694519. The cubic root of 11715561 is about 227.1194685101.

The spelling of 11715561 in words is "eleven million, seven hundred fifteen thousand, five hundred sixty-one".