12405238521 has 16 divisors (see below), whose sum is σ = 18860454144. Its totient is φ = 7184934144.

The previous prime is 12405238493. The next prime is 12405238523. The reversal of 12405238521 is 12583250421.

It is not a de Polignac number, because 12405238521 - 2⁶ = 12405238457 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12405238523) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9354721 + ... + 9356046.

It is an arithmetic number, because the mean of its divisors is an integer number (1178778384).

Almost surely, 2^12405238521 is an apocalyptic number.

It is an amenable number.

12405238521 is a deficient number, since it is larger than the sum of its proper divisors (6455215623).

12405238521 is a wasteful number, since it uses less digits than its factorization.

12405238521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18710800.

The product of its (nonzero) digits is 19200, while the sum is 33.

Adding to 12405238521 its reverse (12583250421), we get a palindrome (24988488942).

The spelling of 12405238521 in words is "twelve billion, four hundred five million, two hundred thirty-eight thousand, five hundred twenty-one".