12638628557 has 4 divisors (see below), whose sum is σ = 12644048220. Its totient is φ = 12633208896.

The previous prime is 12638628523. The next prime is 12638628581. The reversal of 12638628557 is 75582683621.

12638628557 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 2 ways, for example, as 2336175556 + 10302453001 = 48334^2 + 101501^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12638628557 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 12638628499 and 12638628508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12638627557) 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 3 ways as a sum of consecutive naturals, for example, 2706332 + ... + 2710997.

It is an arithmetic number, because the mean of its divisors is an integer number (3161012055).

Almost surely, 2^12638628557 is an apocalyptic number.

It is an amenable number.

12638628557 is a deficient number, since it is larger than the sum of its proper divisors (5419663).

12638628557 is an equidigital number, since it uses as much as digits as its factorization.

12638628557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5419662.

The product of its digits is 4838400, while the sum is 53.

The spelling of 12638628557 in words is "twelve billion, six hundred thirty-eight million, six hundred twenty-eight thousand, five hundred fifty-seven".