12780405 has 24 divisors (see below), whose sum is σ = 24167520. Its totient is φ = 6196320.

The previous prime is 12780373. The next prime is 12780409. The reversal of 12780405 is 50408721.

It is not a de Polignac number, because 12780405 - 2⁵ = 12780373 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12780409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 12415 + ... + 13404.

It is an arithmetic number, because the mean of its divisors is an integer number (1006980).

Almost surely, 2^12780405 is an apocalyptic number.

12780405 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

12780405 is a deficient number, since it is larger than the sum of its proper divisors (11387115).

12780405 is a wasteful number, since it uses less digits than its factorization.

12780405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25841 (or 25838 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 12780405 is about 3574.9692306368. The cubic root of 12780405 is about 233.8019911614.

The spelling of 12780405 in words is "twelve million, seven hundred eighty thousand, four hundred five".