12940409 has 4 divisors (see below), whose sum is σ = 13386660. Its totient is φ = 12494160.

The previous prime is 12940393. The next prime is 12940429. The reversal of 12940409 is 90404921.

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 6325225 + 6615184 = 2515^2 + 2572^2 .

It is a cyclic number.

It is not a de Polignac number, because 12940409 - 2⁴ = 12940393 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 446221 = 12940409 / (1 + 2 + 9 + 4 + 0 + 4 + 0 + 9).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12940429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223082 + ... + 223139.

It is an arithmetic number, because the mean of its divisors is an integer number (3346665).

Almost surely, 2^12940409 is an apocalyptic number.

It is an amenable number.

12940409 is a deficient number, since it is larger than the sum of its proper divisors (446251).

12940409 is an equidigital number, since it uses as much as digits as its factorization.

12940409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 446250.

The product of its (nonzero) digits is 2592, while the sum is 29.

The square root of 12940409 is about 3597.2779987096. The cubic root of 12940409 is about 234.7736404911.

The spelling of 12940409 in words is "twelve million, nine hundred forty thousand, four hundred nine".