11691809 has 4 divisors (see below), whose sum is σ = 11883540. Its totient is φ = 11500080.

The previous prime is 11691793. The next prime is 11691851. The reversal of 11691809 is 90819611.

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

It can be written as a sum of positive squares in 2 ways, for example, as 616225 + 11075584 = 785^2 + 3328^2 .

It is a cyclic number.

It is not a de Polignac number, because 11691809 - 2⁴ = 11691793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11691209) 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, 95774 + ... + 95895.

It is an arithmetic number, because the mean of its divisors is an integer number (2970885).

Almost surely, 2^11691809 is an apocalyptic number.

It is an amenable number.

11691809 is a deficient number, since it is larger than the sum of its proper divisors (191731).

11691809 is an equidigital number, since it uses as much as digits as its factorization.

11691809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 191730.

The product of its (nonzero) digits is 3888, while the sum is 35.

The square root of 11691809 is about 3419.3287352929. The cubic root of 11691809 is about 226.9658781602.

The spelling of 11691809 in words is "eleven million, six hundred ninety-one thousand, eight hundred nine".