12521205538 has 4 divisors (see below), whose sum is σ = 18781808310. Its totient is φ = 6260602768.

The previous prime is 12521205509. The next prime is 12521205539. The reversal of 12521205538 is 83550212521.

12521205538 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 11446218169 + 1074987369 = 106987^2 + 32787^2 .

It is not an unprimeable number, because it can be changed into a 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, 3130301383 + ... + 3130301386.

Almost surely, 2^12521205538 is an apocalyptic number.

12521205538 is a deficient number, since it is larger than the sum of its proper divisors (6260602772).

12521205538 is an equidigital number, since it uses as much as digits as its factorization.

12521205538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6260602771.

The product of its (nonzero) digits is 24000, while the sum is 34.

The spelling of 12521205538 in words is "twelve billion, five hundred twenty-one million, two hundred five thousand, five hundred thirty-eight".