12521205509 has 2 divisors, whose sum is σ = 12521205510. Its totient is φ = 12521205508.

The previous prime is 12521205493. The next prime is 12521205539. The reversal of 12521205509 is 90550212521.

12521205509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12494321284 + 26884225 = 111778^2 + 5185^2 .

It is a cyclic number.

It is not a de Polignac number, because 12521205509 - 2⁴ = 12521205493 is a prime.

It is a super-2 number, since 2×12521205509² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12521205539) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6260602754 + 6260602755.

It is an arithmetic number, because the mean of its divisors is an integer number (6260602755).

Almost surely, 2^12521205509 is an apocalyptic number.

It is an amenable number.

12521205509 is a deficient number, since it is larger than the sum of its proper divisors (1).

12521205509 is an equidigital number, since it uses as much as digits as its factorization.

12521205509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 9000, while the sum is 32.

The spelling of 12521205509 in words is "twelve billion, five hundred twenty-one million, two hundred five thousand, five hundred nine".