21020111111111 has 8 divisors (see below), whose sum is σ = 25436100840480. Its totient is φ = 16957400560128.

The previous prime is 21020111111089. The next prime is 21020111111203. The reversal of 21020111111111 is 11111111102012.

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

It is not a de Polignac number, because 21020111111111 - 2³⁴ = 21002931241927 is a prime.

It is a super-2 number, since 2×21020111111111² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

21020111111111 is a modest number, since divided by 11111111 gives 210201 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21020111111411) 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, 88319794466 + ... + 88319794703.

It is an arithmetic number, because the mean of its divisors is an integer number (3179512605060).

Almost surely, 2^{21020111111111} is an apocalyptic number.

21020111111111 is a deficient number, since it is larger than the sum of its proper divisors (4415989729369).

21020111111111 is a wasteful number, since it uses less digits than its factorization.

21020111111111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 176639589193.

The product of its (nonzero) digits is 4, while the sum is 14.

Adding to 21020111111111 its reverse (11111111102012), we get a palindrome (32131222213123).

Subtracting from 21020111111111 its reverse (11111111102012), we obtain a palindrome (9909000009099).

The spelling of 21020111111111 in words is "twenty-one trillion, twenty billion, one hundred eleven million, one hundred eleven thousand, one hundred eleven".