21312010221 has 16 divisors (see below), whose sum is σ = 28881230400. Its totient is φ = 13977020288.

The previous prime is 21312010219. The next prime is 21312010277. The reversal of 21312010221 is 12201021312.

It is a cyclic number.

It is not a de Polignac number, because 21312010221 - 2¹ = 21312010219 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21312010221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21312010201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 149991 + ... + 255188.

It is an arithmetic number, because the mean of its divisors is an integer number (1805076900).

Almost surely, 2^21312010221 is an apocalyptic number.

It is an amenable number.

21312010221 is a deficient number, since it is larger than the sum of its proper divisors (7569220179).

21312010221 is a wasteful number, since it uses less digits than its factorization.

21312010221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 405468.

The product of its (nonzero) digits is 48, while the sum is 15.

Adding to 21312010221 its reverse (12201021312), we get a palindrome (33513031533).

The spelling of 21312010221 in words is "twenty-one billion, three hundred twelve million, ten thousand, two hundred twenty-one".