21211221213 has 192 divisors, whose sum is σ = 40441669632. Its totient is φ = 10416107520.

The previous prime is 21211221179. The next prime is 21211221223. The reversal of 21211221213 is 31212211212.

21211221213 is a `hidden beast` number, since 21 + 211 + 221 + 213 = 666.

It is not a de Polignac number, because 21211221213 - 2²⁸ = 20942785757 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211221223) 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 in 191 ways as a sum of consecutive naturals, for example, 75484633 + ... + 75484913.

It is an arithmetic number, because the mean of its divisors is an integer number (210633696).

Almost surely, 2^21211221213 is an apocalyptic number.

It is an amenable number.

21211221213 is a deficient number, since it is larger than the sum of its proper divisors (19230448419).

21211221213 is a wasteful number, since it uses less digits than its factorization.

21211221213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 444 (or 441 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

Adding to 21211221213 its reverse (31212211212), we get a palindrome (52423432425).

The spelling of 21211221213 in words is "twenty-one billion, two hundred eleven million, two hundred twenty-one thousand, two hundred thirteen".