12939809 has 4 divisors (see below), whose sum is σ = 12968340. Its totient is φ = 12911280.

The previous prime is 12939793. The next prime is 12939811. The reversal of 12939809 is 90893921.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90893921 = 8219 ⋅11059.

It can be written as a sum of positive squares in 2 ways, for example, as 2795584 + 10144225 = 1672^2 + 3185^2 .

It is a cyclic number.

It is not a de Polignac number, because 12939809 - 2⁴ = 12939793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12939859) 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, 13574 + ... + 14495.

It is an arithmetic number, because the mean of its divisors is an integer number (3242085).

Almost surely, 2^12939809 is an apocalyptic number.

It is an amenable number.

12939809 is a deficient number, since it is larger than the sum of its proper divisors (28531).

12939809 is an equidigital number, since it uses as much as digits as its factorization.

12939809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28530.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 12939809 is about 3597.1946013526. The cubic root of 12939809 is about 234.7700118999.

The spelling of 12939809 in words is "twelve million, nine hundred thirty-nine thousand, eight hundred nine".