12640221021 has 48 divisors (see below), whose sum is σ = 18734289408. Its totient is φ = 7564972800.

The previous prime is 12640221007. The next prime is 12640221053. The reversal of 12640221021 is 12012204621.

It is not a de Polignac number, because 12640221021 - 2¹¹ = 12640218973 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12640221001) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 9790386 + ... + 9791676.

It is an arithmetic number, because the mean of its divisors is an integer number (390297696).

Almost surely, 2^12640221021 is an apocalyptic number.

It is an amenable number.

12640221021 is a deficient number, since it is larger than the sum of its proper divisors (6094068387).

12640221021 is a wasteful number, since it uses less digits than its factorization.

12640221021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1842 (or 1825 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

Adding to 12640221021 its reverse (12012204621), we get a palindrome (24652425642).

The spelling of 12640221021 in words is "twelve billion, six hundred forty million, two hundred twenty-one thousand, twenty-one".