11565591 has 4 divisors (see below), whose sum is σ = 15420792. Its totient is φ = 7710392.

The previous prime is 11565583. The next prime is 11565613. The reversal of 11565591 is 19556511.

11565591 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 11565591 - 2³ = 11565583 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11565551) 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, 1927596 + ... + 1927601.

It is an arithmetic number, because the mean of its divisors is an integer number (3855198).

Almost surely, 2^11565591 is an apocalyptic number.

11565591 is a deficient number, since it is larger than the sum of its proper divisors (3855201).

11565591 is an equidigital number, since it uses as much as digits as its factorization.

11565591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3855200.

The product of its digits is 6750, while the sum is 33.

The square root of 11565591 is about 3400.8221064913. The cubic root of 11565591 is about 226.1461906887.

The spelling of 11565591 in words is "eleven million, five hundred sixty-five thousand, five hundred ninety-one".