21220311213 has 6 divisors (see below), whose sum is σ = 30651560654. Its totient is φ = 14146874136.

The previous prime is 21220311209. The next prime is 21220311263. The reversal of 21220311213 is 31211302212.

It can be written as a sum of positive squares in only one way, i.e., 19442676969 + 1777634244 = 139437^2 + 42162^2 .

It is not a de Polignac number, because 21220311213 - 2² = 21220311209 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 (21220311263) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1178906170 + ... + 1178906187.

Almost surely, 2^21220311213 is an apocalyptic number.

It is an amenable number.

21220311213 is a deficient number, since it is larger than the sum of its proper divisors (9431249441).

21220311213 is a wasteful number, since it uses less digits than its factorization.

21220311213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2357812363 (or 2357812360 counting only the distinct ones).

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

Adding to 21220311213 its reverse (31211302212), we get a palindrome (52431613425).

Subtracting 21220311213 from its reverse (31211302212), we obtain a palindrome (9990990999).

The spelling of 21220311213 in words is "twenty-one billion, two hundred twenty million, three hundred eleven thousand, two hundred thirteen".