11565221 has 4 divisors (see below), whose sum is σ = 11586912. Its totient is φ = 11543532.

The previous prime is 11565209. The next prime is 11565233. The reversal of 11565221 is 12256511.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 12256511 = 67 ⋅182933.

It is an interprime number because it is at equal distance from previous prime (11565209) and next prime (11565233).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11565221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11565721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10025 + ... + 11118.

It is an arithmetic number, because the mean of its divisors is an integer number (2896728).

Almost surely, 2^11565221 is an apocalyptic number.

It is an amenable number.

11565221 is a deficient number, since it is larger than the sum of its proper divisors (21691).

11565221 is an equidigital number, since it uses as much as digits as its factorization.

11565221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21690.

The product of its digits is 600, while the sum is 23.

The square root of 11565221 is about 3400.7677074449. The cubic root of 11565221 is about 226.1437790817.

The spelling of 11565221 in words is "eleven million, five hundred sixty-five thousand, two hundred twenty-one".