21021111121111 has 8 divisors (see below), whose sum is σ = 21155847977264. Its totient is φ = 20886384954240.

The previous prime is 21021111121097. The next prime is 21021111121123. The reversal of 21021111121111 is 11112111112012.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21021111121111 - 2⁵ = 21021111121079 is a prime.

It is a super-2 number, since 2×21021111121111² (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 (21021111121211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1292191 + ... + 6611503.

It is an arithmetic number, because the mean of its divisors is an integer number (2644480997158).

Almost surely, 2^{21021111121111} is an apocalyptic number.

21021111121111 is a deficient number, since it is larger than the sum of its proper divisors (134736856153).

21021111121111 is a wasteful number, since it uses less digits than its factorization.

21021111121111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5344641.

The product of its (nonzero) digits is 8, while the sum is 16.

Adding to 21021111121111 its reverse (11112111112012), we get a palindrome (32133222233123).

Subtracting from 21021111121111 its reverse (11112111112012), we obtain a palindrome (9909000009099).

The spelling of 21021111121111 in words is "twenty-one trillion, twenty-one billion, one hundred eleven million, one hundred twenty-one thousand, one hundred eleven".