21121111212111 has 48 divisors (see below), whose sum is σ = 30946436801280. Its totient is φ = 13880061262080.

The previous prime is 21121111212031. The next prime is 21121111212119. The reversal of 21121111212111 is 11121211112112.

21121111212111 is a `hidden beast` number, since 211 + 21 + 111 + 212 + 111 = 666.

It is not a de Polignac number, because 21121111212111 - 2²³ = 21121102823503 is a prime.

It is a super-2 number, since 2×21121111212111² (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 (21121111212119) 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, 293137656 + ... + 293209698.

It is an arithmetic number, because the mean of its divisors is an integer number (644717433360).

Almost surely, 2^{21121111212111} is an apocalyptic number.

21121111212111 is a deficient number, since it is larger than the sum of its proper divisors (9825325589169).

21121111212111 is a wasteful number, since it uses less digits than its factorization.

21121111212111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73836 (or 73833 counting only the distinct ones).

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

Adding to 21121111212111 its reverse (11121211112112), we get a palindrome (32242322324223).

Subtracting from 21121111212111 its reverse (11121211112112), we obtain a palindrome (9999900099999).

The spelling of 21121111212111 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred eleven million, two hundred twelve thousand, one hundred eleven".