12561909 has 4 divisors (see below), whose sum is σ = 16749216. Its totient is φ = 8374604.

The previous prime is 12561889. The next prime is 12561911. The reversal of 12561909 is 90916521.

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 a cyclic number.

It is not a de Polignac number, because 12561909 - 2⁵ = 12561877 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12561909.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12561509) 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, 2093649 + ... + 2093654.

It is an arithmetic number, because the mean of its divisors is an integer number (4187304).

Almost surely, 2^12561909 is an apocalyptic number.

It is an amenable number.

12561909 is a deficient number, since it is larger than the sum of its proper divisors (4187307).

12561909 is an equidigital number, since it uses as much as digits as its factorization.

12561909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4187306.

The product of its (nonzero) digits is 4860, while the sum is 33.

The square root of 12561909 is about 3544.2783468571. The cubic root of 12561909 is about 232.4619523819.

The spelling of 12561909 in words is "twelve million, five hundred sixty-one thousand, nine hundred nine".