11912809 has 4 divisors (see below), whose sum is σ = 11965060. Its totient is φ = 11860560.

The previous prime is 11912807. The next prime is 11912821. The reversal of 11912809 is 90821911.

11912809 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 8832784 + 3080025 = 2972^2 + 1755^2 .

It is a cyclic number.

It is not a de Polignac number, because 11912809 - 2¹ = 11912807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11912807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 25782 + ... + 26239.

It is an arithmetic number, because the mean of its divisors is an integer number (2991265).

Almost surely, 2^11912809 is an apocalyptic number.

It is an amenable number.

11912809 is a deficient number, since it is larger than the sum of its proper divisors (52251).

11912809 is an equidigital number, since it uses as much as digits as its factorization.

11912809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52250.

The product of its (nonzero) digits is 1296, while the sum is 31.

The square root of 11912809 is about 3451.4937346025. The cubic root of 11912809 is about 228.3870068765.

It can be divided in two parts, 11912 and 809, that added together give a palindrome (12721).

The spelling of 11912809 in words is "eleven million, nine hundred twelve thousand, eight hundred nine".