12729013021 has 4 divisors (see below), whose sum is σ = 12969183132. Its totient is φ = 12488842912.

The previous prime is 12729013009. The next prime is 12729013039. The reversal of 12729013021 is 12031092721.

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 10017207396 + 2711805625 = 100086^2 + 52075^2 .

It is a cyclic number.

It is not a de Polignac number, because 12729013021 - 2⁹ = 12729012509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12729013001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 120084976 + ... + 120085081.

It is an arithmetic number, because the mean of its divisors is an integer number (3242295783).

Almost surely, 2^12729013021 is an apocalyptic number.

It is an amenable number.

12729013021 is a deficient number, since it is larger than the sum of its proper divisors (240170111).

12729013021 is an equidigital number, since it uses as much as digits as its factorization.

12729013021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240170110.

The product of its (nonzero) digits is 1512, while the sum is 28.

The spelling of 12729013021 in words is "twelve billion, seven hundred twenty-nine million, thirteen thousand, twenty-one".