12531209 has 2 divisors, whose sum is σ = 12531210. Its totient is φ = 12531208.

The previous prime is 12531191. The next prime is 12531221. The reversal of 12531209 is 90213521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10220809 + 2310400 = 3197^2 + 1520^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12531209 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (12531709) 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, 6265604 + 6265605.

It is an arithmetic number, because the mean of its divisors is an integer number (6265605).

Almost surely, 2^12531209 is an apocalyptic number.

It is an amenable number.

12531209 is a deficient number, since it is larger than the sum of its proper divisors (1).

12531209 is an equidigital number, since it uses as much as digits as its factorization.

12531209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 23.

The square root of 12531209 is about 3539.9447735805. The cubic root of 12531209 is about 232.2724269541.

The spelling of 12531209 in words is "twelve million, five hundred thirty-one thousand, two hundred nine".