12778409 has 16 divisors (see below), whose sum is σ = 15375360. Its totient is φ = 10383120.

The previous prime is 12778399. The next prime is 12778421. The reversal of 12778409 is 90487721.

It is not a de Polignac number, because 12778409 - 2¹⁶ = 12712873 is a prime.

It is a Smith number, since the sum of its digits (38) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (12778499) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22094 + ... + 22664.

It is an arithmetic number, because the mean of its divisors is an integer number (960960).

Almost surely, 2^12778409 is an apocalyptic number.

It is an amenable number.

12778409 is a deficient number, since it is larger than the sum of its proper divisors (2596951).

12778409 is a wasteful number, since it uses less digits than its factorization.

12778409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 740.

The product of its (nonzero) digits is 28224, while the sum is 38.

The square root of 12778409 is about 3574.6900564944. The cubic root of 12778409 is about 233.7898190622.

The spelling of 12778409 in words is "twelve million, seven hundred seventy-eight thousand, four hundred nine".