11913565 has 4 divisors (see below), whose sum is σ = 14296284. Its totient is φ = 9530848.

The previous prime is 11913553. The next prime is 11913581. The reversal of 11913565 is 56531911.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56531911 = 181 ⋅312331.

It can be written as a sum of positive squares in 2 ways, for example, as 6728836 + 5184729 = 2594^2 + 2277^2 .

It is a cyclic number.

It is not a de Polignac number, because 11913565 - 2⁹ = 11913053 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1191352 + ... + 1191361.

It is an arithmetic number, because the mean of its divisors is an integer number (3574071).

Almost surely, 2^11913565 is an apocalyptic number.

It is an amenable number.

11913565 is a deficient number, since it is larger than the sum of its proper divisors (2382719).

11913565 is an equidigital number, since it uses as much as digits as its factorization.

11913565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2382718.

The product of its digits is 4050, while the sum is 31.

The square root of 11913565 is about 3451.6032506648. The cubic root of 11913565 is about 228.3918380047.

The spelling of 11913565 in words is "eleven million, nine hundred thirteen thousand, five hundred sixty-five".