11665521 has 12 divisors (see below), whose sum is σ = 19257472. Its totient is φ = 6665976.

The previous prime is 11665501. The next prime is 11665523. The reversal of 11665521 is 12556611.

It is a happy number.

11665521 is a `hidden beast` number, since 1 + 1 + 6 + 655 + 2 + 1 = 666.

It is not a de Polignac number, because 11665521 - 2²¹ = 9568369 is a prime.

It is a Duffinian number.

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (11665523) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 92521 + ... + 92646.

Almost surely, 2^11665521 is an apocalyptic number.

It is an amenable number.

11665521 is a deficient number, since it is larger than the sum of its proper divisors (7591951).

11665521 is a wasteful number, since it uses less digits than its factorization.

11665521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185180 (or 185177 counting only the distinct ones).

The product of its digits is 1800, while the sum is 27.

The square root of 11665521 is about 3415.4825427749. The cubic root of 11665521 is about 226.7956462682.

The spelling of 11665521 in words is "eleven million, six hundred sixty-five thousand, five hundred twenty-one".