12125809 has 2 divisors, whose sum is σ = 12125810. Its totient is φ = 12125808.

The previous prime is 12125803. The next prime is 12125837. The reversal of 12125809 is 90852121.

It is an a-pointer prime, because the next prime (12125837) can be obtained adding 12125809 to its sum of digits (28).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7728400 + 4397409 = 2780^2 + 2097^2 .

It is a cyclic number.

It is not a de Polignac number, because 12125809 - 2¹⁵ = 12093041 is a prime.

It is not a weakly prime, because it can be changed into another prime (12125803) 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 as a sum of consecutive naturals, namely, 6062904 + 6062905.

It is an arithmetic number, because the mean of its divisors is an integer number (6062905).

Almost surely, 2^12125809 is an apocalyptic number.

It is an amenable number.

12125809 is a deficient number, since it is larger than the sum of its proper divisors (1).

12125809 is an equidigital number, since it uses as much as digits as its factorization.

12125809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 28.

The square root of 12125809 is about 3482.2132329885. The cubic root of 12125809 is about 229.7401539304.

It can be divided in two parts, 1212 and 5809, that added together give a triangular number (7021 = T₁₁₈).

The spelling of 12125809 in words is "twelve million, one hundred twenty-five thousand, eight hundred nine".