12781209 has 16 divisors (see below), whose sum is σ = 19875200. Its totient is φ = 7302960.

The previous prime is 12781193. The next prime is 12781267. The reversal of 12781209 is 90218721.

It is not a de Polignac number, because 12781209 - 2⁴ = 12781193 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12781009) 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, 5182 + ... + 7239.

It is an arithmetic number, because the mean of its divisors is an integer number (1242200).

Almost surely, 2^12781209 is an apocalyptic number.

It is an amenable number.

12781209 is a deficient number, since it is larger than the sum of its proper divisors (7093991).

12781209 is an equidigital number, since it uses as much as digits as its factorization.

12781209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12445 (or 12431 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 12781209 is about 3575.0816773886. The cubic root of 12781209 is about 233.8068937932.

The spelling of 12781209 in words is "twelve million, seven hundred eighty-one thousand, two hundred nine".