21023111011 has 16 divisors (see below), whose sum is σ = 24269808384. Its totient is φ = 17837525664.

The previous prime is 21023111009. The next prime is 21023111077. The reversal of 21023111011 is 11011132012.

It is a happy number.

It is not a de Polignac number, because 21023111011 - 2¹ = 21023111009 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21023110982 and 21023111000.

It is not an unprimeable number, because it can be changed into a prime (21023111611) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1018156 + ... + 1038598.

It is an arithmetic number, because the mean of its divisors is an integer number (1516863024).

Almost surely, 2^21023111011 is an apocalyptic number.

21023111011 is a deficient number, since it is larger than the sum of its proper divisors (3246697373).

21023111011 is a wasteful number, since it uses less digits than its factorization.

21023111011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21930.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 21023111011 its reverse (11011132012), we get a palindrome (32034243023).

It can be divided in two parts, 2102 and 3111011, that added together give a palindrome (3113113).

The spelling of 21023111011 in words is "twenty-one billion, twenty-three million, one hundred eleven thousand, eleven".