21211111212111 has 48 divisors (see below), whose sum is σ = 31911998713920. Its totient is φ = 13563722833920.

The previous prime is 21211111212107. The next prime is 21211111212133. The reversal of 21211111212111 is 11121211111212.

21211111212111 is a `hidden beast` number, since 21 + 211 + 111 + 212 + 111 = 666.

It is not a de Polignac number, because 21211111212111 - 2² = 21211111212107 is a prime.

It is a super-2 number, since 2×21211111212111² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211111112111) 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, 403157775 + ... + 403210383.

It is an arithmetic number, because the mean of its divisors is an integer number (664833306540).

Almost surely, 2^{21211111212111} is an apocalyptic number.

21211111212111 is a deficient number, since it is larger than the sum of its proper divisors (10700887501809).

21211111212111 is a wasteful number, since it uses less digits than its factorization.

21211111212111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 69776 (or 69773 counting only the distinct ones).

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

Adding to 21211111212111 its reverse (11121211111212), we get a palindrome (32332322323323).

It can be divided in two parts, 21211111212 and 111, that multiplied together give a palindrome (2354433344532).

The spelling of 21211111212111 in words is "twenty-one trillion, two hundred eleven billion, one hundred eleven million, two hundred twelve thousand, one hundred eleven".