21111111221211 has 40 divisors (see below), whose sum is σ = 35513076031488. Its totient is φ = 12381883398000.

The previous prime is 21111111221203. The next prime is 21111111221371. The reversal of 21111111221211 is 11212211111112.

21111111221211 is a `hidden beast` number, since 211 + 1 + 11 + 11 + 221 + 211 = 666.

It is not a de Polignac number, because 21111111221211 - 2³ = 21111111221203 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21111111221201) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 382129275 + ... + 382184516.

Almost surely, 2^{21111111221211} is an apocalyptic number.

21111111221211 is a deficient number, since it is larger than the sum of its proper divisors (14401964810277).

21111111221211 is a wasteful number, since it uses less digits than its factorization.

21111111221211 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 764313845 (or 764313836 counting only the distinct ones).

The product of its digits is 16, while the sum is 18.

Adding to 21111111221211 its reverse (11212211111112), we get a palindrome (32323322332323).

The spelling of 21111111221211 in words is "twenty-one trillion, one hundred eleven billion, one hundred eleven million, two hundred twenty-one thousand, two hundred eleven".