21212131222111 has 4 divisors (see below), whose sum is σ = 21339149972112. Its totient is φ = 21085112472112.

The previous prime is 21212131222063. The next prime is 21212131222153. The reversal of 21212131222111 is 11122213121212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21212131222111 - 2²⁵ = 21212097667679 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212131222181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 63509374750 + ... + 63509375083.

It is an arithmetic number, because the mean of its divisors is an integer number (5334787493028).

Almost surely, 2^{21212131222111} is an apocalyptic number.

21212131222111 is a deficient number, since it is larger than the sum of its proper divisors (127018750001).

21212131222111 is a wasteful number, since it uses less digits than its factorization.

21212131222111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127018750000.

The product of its digits is 192, while the sum is 22.

Adding to 21212131222111 its reverse (11122213121212), we get a palindrome (32334344343323).

The spelling of 21212131222111 in words is "twenty-one trillion, two hundred twelve billion, one hundred thirty-one million, two hundred twenty-two thousand, one hundred eleven".