12521643651 has 24 divisors (see below), whose sum is σ = 19737157440. Its totient is φ = 7586535600.

The previous prime is 12521643643. The next prime is 12521643653. The reversal of 12521643651 is 15634612521.

12521643651 is a `hidden beast` number, since 1 + 2 + 5 + 2 + 1 + 643 + 6 + 5 + 1 = 666.

12521643651 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 12521643651 - 2³ = 12521643643 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12521643653) 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 in 23 ways as a sum of consecutive naturals, for example, 335820 + ... + 371238.

It is an arithmetic number, because the mean of its divisors is an integer number (822381560).

Almost surely, 2^12521643651 is an apocalyptic number.

12521643651 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

12521643651 is a deficient number, since it is larger than the sum of its proper divisors (7215513789).

12521643651 is a wasteful number, since it uses less digits than its factorization.

12521643651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39007 (or 39004 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The spelling of 12521643651 in words is "twelve billion, five hundred twenty-one million, six hundred forty-three thousand, six hundred fifty-one".