12905309 has 4 divisors (see below), whose sum is σ = 12959100. Its totient is φ = 12851520.

The previous prime is 12905287. The next prime is 12905311. The reversal of 12905309 is 90350921.

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 3694084 + 9211225 = 1922^2 + 3035^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12905309 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12905209) 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, 26534 + ... + 27015.

It is an arithmetic number, because the mean of its divisors is an integer number (3239775).

Almost surely, 2^12905309 is an apocalyptic number.

It is an amenable number.

12905309 is a deficient number, since it is larger than the sum of its proper divisors (53791).

12905309 is an equidigital number, since it uses as much as digits as its factorization.

12905309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53790.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 12905309 is about 3592.3959971028. The cubic root of 12905309 is about 234.5611789767.

The spelling of 12905309 in words is "twelve million, nine hundred five thousand, three hundred nine".