21121233212111 has 4 divisors (see below), whose sum is σ = 22232877065400. Its totient is φ = 20009589358824.

The previous prime is 21121233212089. The next prime is 21121233212141. The reversal of 21121233212111 is 11121233212112.

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 21121233212111 - 2¹⁰ = 21121233211087 is a prime.

It is a super-2 number, since 2×21121233212111² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121233212141) 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, 555821926616 + ... + 555821926653.

It is an arithmetic number, because the mean of its divisors is an integer number (5558219266350).

Almost surely, 2^{21121233212111} is an apocalyptic number.

21121233212111 is a deficient number, since it is larger than the sum of its proper divisors (1111643853289).

21121233212111 is a wasteful number, since it uses less digits than its factorization.

21121233212111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1111643853288.

The product of its digits is 288, while the sum is 23.

Adding to 21121233212111 its reverse (11121233212112), we get a palindrome (32242466424223).

Subtracting from 21121233212111 its reverse (11121233212112), we obtain a palindrome (9999999999999).

The spelling of 21121233212111 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred thirty-three million, two hundred twelve thousand, one hundred eleven".