21211211213 has 2 divisors, whose sum is σ = 21211211214. Its totient is φ = 21211211212.

The previous prime is 21211211209. The next prime is 21211211227. The reversal of 21211211213 is 31211211212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21188295844 + 22915369 = 145562^2 + 4787^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211211213 - 2² = 21211211209 is a prime.

It is a super-2 number, since 2×21211211213² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21211211191 and 21211211200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21211211243) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605605606 + 10605605607.

It is an arithmetic number, because the mean of its divisors is an integer number (10605605607).

Almost surely, 2^21211211213 is an apocalyptic number.

It is an amenable number.

21211211213 is a deficient number, since it is larger than the sum of its proper divisors (1).

21211211213 is an equidigital number, since it uses as much as digits as its factorization.

21211211213 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48, while the sum is 17.

Adding to 21211211213 its reverse (31211211212), we get a palindrome (52422422425).

Subtracting 21211211213 from its reverse (31211211212), we obtain a palindrome (9999999999).

The spelling of 21211211213 in words is "twenty-one billion, two hundred eleven million, two hundred eleven thousand, two hundred thirteen".