12758721921 has 12 divisors (see below), whose sum is σ = 20104652880. Its totient is φ = 7732558680.

The previous prime is 12758721889. The next prime is 12758721923. The reversal of 12758721921 is 12912785721.

12758721921 is a `hidden beast` number, since 1 + 27 + 587 + 21 + 9 + 21 = 666.

12758721921 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 12758721921 - 2⁵ = 12758721889 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12758721923) 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 11 ways as a sum of consecutive naturals, for example, 64437891 + ... + 64438088.

It is an arithmetic number, because the mean of its divisors is an integer number (1675387740).

Almost surely, 2^12758721921 is an apocalyptic number.

12758721921 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12758721921 is a deficient number, since it is larger than the sum of its proper divisors (7345930959).

12758721921 is a wasteful number, since it uses less digits than its factorization.

12758721921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128875996 (or 128875993 counting only the distinct ones).

The product of its digits is 141120, while the sum is 45.

The spelling of 12758721921 in words is "twelve billion, seven hundred fifty-eight million, seven hundred twenty-one thousand, nine hundred twenty-one".