12778621538 has 16 divisors (see below), whose sum is σ = 20468540160. Its totient is φ = 5969989200.

The previous prime is 12778621529. The next prime is 12778621601. The reversal of 12778621538 is 83512687721.

12778621538 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×12778621538² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 3551768 + ... + 3555363.

It is an arithmetic number, because the mean of its divisors is an integer number (1279283760).

Almost surely, 2^12778621538 is an apocalyptic number.

12778621538 is a deficient number, since it is larger than the sum of its proper divisors (7689918622).

12778621538 is a wasteful number, since it uses less digits than its factorization.

12778621538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7107193.

The product of its digits is 1128960, while the sum is 50.

The spelling of 12778621538 in words is "twelve billion, seven hundred seventy-eight million, six hundred twenty-one thousand, five hundred thirty-eight".