21021011213 has 2 divisors, whose sum is σ = 21021011214. Its totient is φ = 21021011212.

The previous prime is 21021011191. The next prime is 21021011239. The reversal of 21021011213 is 31211012012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11084510089 + 9936501124 = 105283^2 + 99682^2 .

It is a cyclic number.

It is not a de Polignac number, because 21021011213 - 2¹⁴ = 21020994829 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021011813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510505606 + 10510505607.

It is an arithmetic number, because the mean of its divisors is an integer number (10510505607).

Almost surely, 2^21021011213 is an apocalyptic number.

It is an amenable number.

21021011213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021011213 is an equidigital number, since it uses as much as digits as its factorization.

21021011213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 14.

Adding to 21021011213 its reverse (31211012012), we get a palindrome (52232023225).

The spelling of 21021011213 in words is "twenty-one billion, twenty-one million, eleven thousand, two hundred thirteen".