21121211210211 has 72 divisors (see below), whose sum is σ = 36336021424560. Its totient is φ = 11781666981504.

The previous prime is 21121211210189. The next prime is 21121211210221. The reversal of 21121211210211 is 11201211212112.

It is a happy number.

21121211210211 is a `hidden beast` number, since 2 + 11 + 21 + 211 + 210 + 211 = 666.

It is not a de Polignac number, because 21121211210211 - 2²⁶ = 21121144101347 is a prime.

It is a super-2 number, since 2×21121211210211² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121211210221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 32081901 + ... + 32733633.

It is an arithmetic number, because the mean of its divisors is an integer number (504666964230).

Almost surely, 2^{21121211210211} is an apocalyptic number.

21121211210211 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21121211210211 is a deficient number, since it is larger than the sum of its proper divisors (15214810214349).

21121211210211 is a wasteful number, since it uses less digits than its factorization.

21121211210211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 653505 (or 653495 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21121211210211 its reverse (11201211212112), we get a palindrome (32322422422323).

The spelling of 21121211210211 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred eleven million, two hundred ten thousand, two hundred eleven".