21221310213 has 6 divisors (see below), whose sum is σ = 30653003654. Its totient is φ = 14147540136.

The previous prime is 21221310211. The next prime is 21221310221. The reversal of 21221310213 is 31201312212.

It can be written as a sum of positive squares in only one way, i.e., 18555343524 + 2665966689 = 136218^2 + 51633^2 .

It is not a de Polignac number, because 21221310213 - 2¹ = 21221310211 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 (21221310211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1178961670 + ... + 1178961687.

Almost surely, 2^21221310213 is an apocalyptic number.

It is an amenable number.

21221310213 is a deficient number, since it is larger than the sum of its proper divisors (9431693441).

21221310213 is a wasteful number, since it uses less digits than its factorization.

21221310213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2357923363 (or 2357923360 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 21221310213 its reverse (31201312212), we get a palindrome (52422622425).

The spelling of 21221310213 in words is "twenty-one billion, two hundred twenty-one million, three hundred ten thousand, two hundred thirteen".