12538721566 has 64 divisors (see below), whose sum is σ = 23063685120. Its totient is φ = 4993164000.

The previous prime is 12538721537. The next prime is 12538721567. The reversal of 12538721566 is 66512783521.

12538721566 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12538721567) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4471921 + ... + 4474723.

It is an arithmetic number, because the mean of its divisors is an integer number (360370080).

Almost surely, 2^12538721566 is an apocalyptic number.

12538721566 is a deficient number, since it is larger than the sum of its proper divisors (10524963554).

12538721566 is a wasteful number, since it uses less digits than its factorization.

12538721566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3149.

The product of its digits is 604800, while the sum is 46.

The spelling of 12538721566 in words is "twelve billion, five hundred thirty-eight million, seven hundred twenty-one thousand, five hundred sixty-six".