21212221011111 has 48 divisors (see below), whose sum is σ = 33556136769792. Its totient is φ = 12832628774400.

The previous prime is 21212221011083. The next prime is 21212221011221. The reversal of 21212221011111 is 11111012221212.

It is a happy number.

21212221011111 is a `hidden beast` number, since 212 + 122 + 210 + 11 + 111 = 666.

It is not a de Polignac number, because 21212221011111 - 2¹⁸ = 21212220748967 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212221010111) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 12195571 + ... + 13825931.

It is an arithmetic number, because the mean of its divisors is an integer number (699086182704).

Almost surely, 2^{21212221011111} is an apocalyptic number.

21212221011111 is a deficient number, since it is larger than the sum of its proper divisors (12343915758681).

21212221011111 is a wasteful number, since it uses less digits than its factorization.

21212221011111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1632264 (or 1632261 counting only the distinct ones).

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

Adding to 21212221011111 its reverse (11111012221212), we get a palindrome (32323233232323).

The spelling of 21212221011111 in words is "twenty-one trillion, two hundred twelve billion, two hundred twenty-one million, eleven thousand, one hundred eleven".