21212001222111 has 64 divisors (see below), whose sum is σ = 36443995683840. Its totient is φ = 11942780797440.

The previous prime is 21212001222053. The next prime is 21212001222119. The reversal of 21212001222111 is 11122210021212.

21212001222111 is a `hidden beast` number, since 212 + 120 + 0 + 1 + 222 + 111 = 666.

It is not a de Polignac number, because 21212001222111 - 2¹⁵ = 21212001189343 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212001222119) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12605211 + ... + 14188563.

It is an arithmetic number, because the mean of its divisors is an integer number (569437432560).

Almost surely, 2^{21212001222111} is an apocalyptic number.

21212001222111 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21212001222111 is a deficient number, since it is larger than the sum of its proper divisors (15231994461729).

21212001222111 is a wasteful number, since it uses less digits than its factorization.

21212001222111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1584413 (or 1584407 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

Adding to 21212001222111 its reverse (11122210021212), we get a palindrome (32334211243323).

The spelling of 21212001222111 in words is "twenty-one trillion, two hundred twelve billion, one million, two hundred twenty-two thousand, one hundred eleven".