12857209 has 2 divisors, whose sum is σ = 12857210. Its totient is φ = 12857208.

The previous prime is 12857147. The next prime is 12857239. The reversal of 12857209 is 90275821.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11424400 + 1432809 = 3380^2 + 1197^2 .

It is a cyclic number.

It is not a de Polignac number, because 12857209 - 2¹³ = 12849017 is a prime.

It is not a weakly prime, because it can be changed into another prime (12857239) 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 as a sum of consecutive naturals, namely, 6428604 + 6428605.

It is an arithmetic number, because the mean of its divisors is an integer number (6428605).

Almost surely, 2^12857209 is an apocalyptic number.

It is an amenable number.

12857209 is a deficient number, since it is larger than the sum of its proper divisors (1).

12857209 is an equidigital number, since it uses as much as digits as its factorization.

12857209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 12857209 is about 3585.6950511721. The cubic root of 12857209 is about 234.2694014130.

The spelling of 12857209 in words is "twelve million, eight hundred fifty-seven thousand, two hundred nine".