11665921 has 4 divisors (see below), whose sum is σ = 11703744. Its totient is φ = 11628100.

The previous prime is 11665903. The next prime is 11665931. The reversal of 11665921 is 12956611.

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-11665921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11665931) 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, 18445 + ... + 19066.

It is an arithmetic number, because the mean of its divisors is an integer number (2925936).

Almost surely, 2^11665921 is an apocalyptic number.

It is an amenable number.

11665921 is a deficient number, since it is larger than the sum of its proper divisors (37823).

11665921 is an equidigital number, since it uses as much as digits as its factorization.

11665921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37822.

The product of its digits is 3240, while the sum is 31.

The square root of 11665921 is about 3415.5410991525. The cubic root of 11665921 is about 226.7982384434.

The spelling of 11665921 in words is "eleven million, six hundred sixty-five thousand, nine hundred twenty-one".