12905809 has 4 divisors (see below), whose sum is σ = 14749504. Its totient is φ = 11062116.

The previous prime is 12905803. The next prime is 12905861. The reversal of 12905809 is 90850921.

12905809 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 a cyclic number.

It is not a de Polignac number, because 12905809 - 2⁷ = 12905681 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12905803) 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, 921837 + ... + 921850.

It is an arithmetic number, because the mean of its divisors is an integer number (3687376).

Almost surely, 2^12905809 is an apocalyptic number.

It is an amenable number.

12905809 is a deficient number, since it is larger than the sum of its proper divisors (1843695).

12905809 is an equidigital number, since it uses as much as digits as its factorization.

12905809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1843694.

The product of its (nonzero) digits is 6480, while the sum is 34.

The square root of 12905809 is about 3592.4655878658. The cubic root of 12905809 is about 234.5642081970.

The spelling of 12905809 in words is "twelve million, nine hundred five thousand, eight hundred nine".