12491809 has 4 divisors (see below), whose sum is σ = 13627440. Its totient is φ = 11356180.

The previous prime is 12491807. The next prime is 12491819. The reversal of 12491809 is 90819421.

12491809 is digitally balanced in base 2, 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, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 12491809 - 2¹ = 12491807 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12491807) 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, 567799 + ... + 567820.

It is an arithmetic number, because the mean of its divisors is an integer number (3406860).

Almost surely, 2^12491809 is an apocalyptic number.

It is an amenable number.

12491809 is a deficient number, since it is larger than the sum of its proper divisors (1135631).

12491809 is a wasteful number, since it uses less digits than its factorization.

12491809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1135630.

The product of its (nonzero) digits is 5184, while the sum is 34.

The square root of 12491809 is about 3534.3753337754. The cubic root of 12491809 is about 232.0287382652.

The spelling of 12491809 in words is "twelve million, four hundred ninety-one thousand, eight hundred nine".