21212110221111 has 16 divisors (see below), whose sum is σ = 31427172933120. Its totient is φ = 14140585808280.

The previous prime is 21212110221091. The next prime is 21212110221121. The reversal of 21212110221111 is 11112201121212.

It is a happy number.

21212110221111 is a `hidden beast` number, since 2 + 121 + 211 + 0 + 221 + 111 = 666.

It is not a de Polignac number, because 21212110221111 - 2¹¹ = 21212110219063 is a prime.

It is a super-4 number, since 4×21212110221111⁴ (a number of 54 digits) contains 4444 as substring. Note that it is a super-d number also for d = 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212110221121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22331865 + ... + 23262338.

It is an arithmetic number, because the mean of its divisors is an integer number (1964198308320).

Almost surely, 2^{21212110221111} is an apocalyptic number.

21212110221111 is a deficient number, since it is larger than the sum of its proper divisors (10215062712009).

21212110221111 is a wasteful number, since it uses less digits than its factorization.

21212110221111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45611443 (or 45611437 counting only the distinct ones).

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

Adding to 21212110221111 its reverse (11112201121212), we get a palindrome (32324311342323).

The spelling of 21212110221111 in words is "twenty-one trillion, two hundred twelve billion, one hundred ten million, two hundred twenty-one thousand, one hundred eleven".