12638628581 has 2 divisors, whose sum is σ = 12638628582. Its totient is φ = 12638628580.

The previous prime is 12638628523. The next prime is 12638628641. The reversal of 12638628581 is 18582683621.

12638628581 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., 6828377956 + 5810250625 = 82634^2 + 76225^2 .

It is an emirp because it is prime and its reverse (18582683621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12638628581 - 2¹⁰ = 12638627557 is a prime.

It is a super-2 number, since 2×12638628581² (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 (12638678581) 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, 6319314290 + 6319314291.

It is an arithmetic number, because the mean of its divisors is an integer number (6319314291).

Almost surely, 2^12638628581 is an apocalyptic number.

It is an amenable number.

12638628581 is a deficient number, since it is larger than the sum of its proper divisors (1).

12638628581 is an equidigital number, since it uses as much as digits as its factorization.

12638628581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1105920, while the sum is 50.

The spelling of 12638628581 in words is "twelve billion, six hundred thirty-eight million, six hundred twenty-eight thousand, five hundred eighty-one".